sph3u+HW

**Grade 11 - SPH3U Homework - 2014**
|| =**Homework/Handouts**= || review problem - the Fg on a 20 kg mass at some distance from Earth is 150 N. find the Fg when the distance is 3.2 times as large. do this using both methods - the answer should be 14.6 N
 * =**Today's Date**= || =**Class Topics and Notes Summary**=
 * Jan 28 || Review of Newton's Law of Universal Gravitation and solving problems using proportions

Introduction to Energy, Work and Power - [|Rube Goldberg Machines] ||

P.110# 12,16,17,18,23

|| 1. Work W = F * D, measured in Newton-metres or Joules (equivalent), force and distance must be in the same direction Work = force * distance (but the force needs to have a component in the direction of motion) Work done = energy used (in a closed or ideal situation) 2. Energy - Work equivalence - in ideal situations (no loss of energy, no friction, etc) the energy used and the work done are EQUAL *problems where objects are being moved vertically require you to account for the force of gravity (Fg = 9.8*mass). We could say that we need 0.01 Newtons of force upward to move the object, but in reality we don't even need 0.01 additional Newtons of force. So our calculation allows for upward F = Fg. 3. Power P = W / t, measured in watts (Joules/sec), the rate of using energy (or of doing work) Power = the rate of doing work. How quickly we get work done. Still dealing with the physics definition of work. Power is measured in watts, but we often use a larger unit - kilowatts. ||
 * Jan 30 || Work, Power and Energy

Practice problems from handout (above)

151 # 1,2,3

153 # 1-4 || 4. Potential (Gravitational) and Kinetic (motion) energy || 160 # 1,2 163 # 1-4 || and finish both the work from yesterday AND today's few problems - the handouts are in pdf format, so you have everything you need.
 * Feb 3 || Calculations for
 * Feb 4 || For next class, you need to read through the following statements about conservation of energy

5. Law of Conservation of (mechanical) Energy - KE + PE = constant (in a closed system) What's a closed system?? Law of conservation of energy - two statements A. Energy is neither created nor destroyed; it just changes from one form to another (generally less useful forms). B. The sum of potential and kinetic energy in a closed system is a constant. However, in the real world, energy transformations almost always result in less useful forms of energy. We refer to this as "entropy". Take the example of a litre of gasoline, which could be used for many things - like driving, cooking, powering a generator, heating a house. Even though heat and sound are forms of energy, they are not very useful; when you turn the furnace down at night, your house "loses" all the heat from the day. We know that it isn't really gone, but there is not an easy way to recover that energy. || Finish work from p 160 and 163 - remember: start with equation one line of substitution final answer with correct units

Then do the following: p 151 # 4 p 153 # 6 p 163 # 5,6 || The sum of the potential energy and the kinetic energy at all points in a closed system is a constant. That is, PE + KE = constant at all points.
 * Feb 6 || In this unit, we will talk about two types of energy - kinetic (motion) and potential (gravitational).

KE = ½mv² and PE = mgh Take a roller coaster as an example of energy conservation in a closed system 250 kg Cart starts at the top (20 m above ground level) with a speed of 4 m/s. Use energy conservation to find the speed at the bottom of the first hill (h= 0), halfway up the next hill (h = 10m) and at the top of the first hill (h = 20 m). Answers are 20.2 m/s, 14.6 m/s and 4 m/s and we can demonstrate that the answers are independent of the mass of the cart. || Homework - finish work from 151, 153, 163 Then do the Physics Energy Review sheet - prob 1,5,6 || In some cases, like energy conservation problems, we assume that systems are 100% efficient. however, we know that there is no such thing as a free lunch (2nd law of thermodynamics, in case you are interested). So we calculate efficiency in one of the following ways: Efficiency = gain in PE / work done = energy gained / energy used = output energy / input energy In its simplest form, Efficiency = what we get / what it costs
 * Feb 10 || 6. Efficiency - ratio of the output work to the input work (or energy) for some system.

Since there is no friction in a closed system, it is like dropping a marble and a rock from the same height; even though they have different masses, they accelerate at the same rate and hit the ground at the same time) refer to Neil Armstrong dropping a feather and a hammer on the moon [|feather] || problems from board efficiency of motors lifting objects up the side of a building || 1.drop a ball from height of 4 m, and it rebounds to 2.85 m. find the efficiency of the system 2. 2.5 kw motor on top of a building is 80% efficient. It raises a 50 kg object by winding up a cable. Determine the speed of the 50 kg object (4.08 m/s) New - what is the same 50 kg object is raised at a speed of 2.5 m/s with the same 80% efficient motor? Find the power of the motor. Olympic Physics - from [|ABC Olympic Website] || Homework p 170 # 1,2 Energy review # 7-9 || [|Lab] for next week - quiz today (to hand in next Tuesday) || [|efficiency handout]
 * Feb 11 || Review of efficiency - 2 problems
 * Feb 13 || Review of efficiency and energy concepts - input work (force * distance) vs output work (gain in energy)

to be handed in by Friday. Here are your work || We calculated speeds of 0.86, 0.906, and 1.04 m/s for hanging masses of 150, 200 and 250 g. The total mass of the system was 1.273 kg, and the accelerating distance was 40 cm In theory, the relationship should be v = 2.48 m^½ which is a root function. The efficiency of the system was between 70% and 80% || Finish the quiz from last week for next Monday's Test || Begin with discussion of earthquakes - location, specific cause, damage - this brings us into a more general discussion of plate tectonics, the Earth's geologic history, and the processes of science. Wave terminology - frequency, period, wavelength, crest, trough, amplitude 2 types of waves - transverse, longitudinal - distinguished by the vibration orientation (across or along the "rest axis") Calculations of wave speed, frequency, wavelength and period ||  || Problem solving Demo of sympathetic vibrations - one object causes another to vibrate. ||
 * Feb 18&20 || Lab - Conservation of Energy || Lab handout ||
 * Feb 24 || Take up work from lab - what is the relationship between the hanging mass and the maximum speed of a physics cart?
 * Feb 25 || Begin new unit on sound and waves
 * Feb 27 || Review of wave speed, frequency, period and wavelength: calculations

p 275 # 1-4 p 282 # 1-6 p 305 # 8,9,11-13 18,20-23, 25-27 p 334 # 19-24 || (they are just energy), but at the point of maximum overlap, the waves build each other up or cancel each other out temporarily. We use geometric addition of waves to find the shape of the wave at maximum overlap. What happens when two waves meet? -they pass through eachother, since waves are just energy being transferred from place to place -they interfere constructively or destructively ONLY when they occupy the same space || p 305 (handouts) I have two things for you to work on today: - Seismology in Japan - an exercise on p-wave and s-wave calculations - bring a compass - problems from the handout - you may have started these already, but likely haven't finished them the speed of sound in air is given by v = 332 + 0.6(T) m/s - where T is degrees celsius || draw your final circles with a compass
 * Mar 3 || Test on work, power, energy, efficiency - half concepts, half calculations ||  ||
 * Mar 4 || Superposition of waves = interference - waves that meet pass through each other
 * 1) 35 a-d, 37 ||
 * Mar 6 || Today Mr Guetter is on the Europe trip - hopefully in Paris by the time you get to class.

p 305 # 8,9,11-13 18,20-23, 25-27 plus # 28,31,32,34 p 334 # 19-24 || to find three (or more distances). Then we draw arcs or circles that represent those distances. With three unique points, the circles should have ONE POINT in common. That point is the epicentre of the earthquake. Graph of density vs speed of sound - in general, the more dense an material is, the faster sound travels through it. Since sound travels as compressional waves, the closer the particles are to each other, the more quickly they can pass from one particle to the next. In gases, the particles are farther apart, so it takes longer for the vibration to pass from one to the next. some speeds to know: air - about 330 m/s, water - 1000-1500 m/s, rock - 3000 - 8000 m/s In air, the temperature makes a huge difference - think about a balloon put in the sunshine or in the freezer. So the speed of sound increases if the air is warmer (the particles are moving faster) and the speed of sound decreases if the air is colder, since the particles are moving slower. || Finish Japan handout Finish problems from 305 and 334 for next class. Answers are on the unit outline || 1. strike a tuning fork and rotate it by your ear. Explain why the sound gets softer and then louder 2. strike a tuning fork and hold the base to a desk top. Explain why the sound gets louder 3. with a slinky and a partner, produce both compressional and transverse waves and notice the following: wave reflection, wave interference 4. with a boom whacker (sound tube) and a tuning fork, explain why holding a tuning fork to an open end of the tube sometimes makes the sound louder and sometimes makes it softer work in class on p 305 and 334 problems. ||  || The rest of you will work on two things: a quiz which covers the first half of this unit, and speed of waves problems that require algebraic solutions. || || - video clip from Big Bang Theory - Sheldon and the costume party. Calculation of apparent frequency: F2 = F1 [ v / (v ± s)] where F1 is the original frequency, v is the speed of sound, and s is the speed of the source. We can determine the + or - intuitively OR we can memorize that - means coming toward and + means going away. Homework problems from handout || p 366 # 58-60 finish algebraic problems handout ||
 * Spring Break ||  ||   ||
 * Mar 17 || Review of work from last class - assignment on Japan earthquake. We use a process called "triangulation"
 * Mar 18 || Demonstrations in class:
 * Mar 20 || Mr Guetter and several students from this class are absent today - Robotics at Waterloo
 * Mar 24 || Doppler effect - the apparent change in frequency of a wave due to the motion of the source or receiver
 * Mar 25 || ** Four variations on a doppler effect problem **

1. car horn has freq of 350 hz, air temp is 20 degrees, car speed is 20 m/s toward you, find the apparent freq. f = 371 hz 2. freq of horn is 350 hz, the apparent freq is 420 hz, air temp is 0 degrees, find the car's speed. v = 55.3 m/s 3. car speed is 100 km/hr away from you, air temp is 10 degrees, the apparent freq is 320 hz, what is the actual freq? f = 346 hz 4. find the air temp if the actual freq is 500 hz, the apparent freq is 460 hz and the car's speed is 30 m/s. T = 22 degrees

Introduction to Real Life Examples of Resonance - start with the Bay of Fundy - thanks to Andre for the explanation! What factors contribute to the World's Highest Tides? ||  || produce such loud sounds? We used a demonstration with tuning forks, a container of water, and different lengths of hard plastic tubing to learn about resonance. Although every textbook uses transverse waves to teach about standing waves in air columns, sound travels through air as a compressional wave. This means that rather than crests and troughs, there are regions of higher and lower air pressure. And the length of the air column determines whether or not there will be resonance for a specific frequency. For closed (at one end) air columns, there is resonance at 1/4 wavelength, 3/4, 5/4, etc. And for open (at both ends) air columns, there is resonance at 1/2 wavelength, 1, 3/2, etc. And we did calculations to show that, despite the difficulty in representing the standing wave clearly, resonance really does occur at very specific lengths for both open and closed columns. The two links to the right are the best examples that I could find on air columns and resonance. || [|visual explanation of air column resonance]
 * Mar 27 || Tuning forks and resonance in air columns. Why do organ pipes and other wind instruments

[|standing wave demo]

p 366 # 47-57 only do two for homework see if you can explain why resonance in air columns follows the given pattern

|| If a problem says the first resonance in a closed tube occurs at 25 cm (which is 1/4 wave), the wavelength is 100 cm If a problem says the third resonance in an open tube occurs at 120 cm (which is 1.5 waves), the wavelength is 80 cm. Spend time reviewing and completing these problems AND preparing for tomorrow's lab on resonance in closed tubes. Calculations of frequency change with strings - four factors that affect the frequency. Know how an increase or decrease in each factor affects the frequency of the string. 1. change in length of string 2. change in tension of string 3. change in diameter of string 4. change in density (material) of string ||  || pick a tuning fork; based on frequency and air temperature, calculate the first two resonant lengths (1/4 and 3/4) take the fork, a plastic tube, and a container of water, and adjust the length of the closed air column until resonance is produced. Compare this length to the calculated value. how close are they? Can you tape two tubes together and produce resonance at the second length? When finished, work on problems with resonance in strings - already mentioned this yesterday. the formulas are on the Sound and Waves PPT handout that we used for the demo. || string problems Review of string calculations - do a two-step problem and convince yourself that the order doesn't matter. But you must use the result of the first calculation as the starting point for the second calculation Introduction to hearing and the human ear ||  || Sound intensity, range of hearing, how the ear works, hearing problems Animation of how the ear works - [] Handout - physics of hearing - be able to explain the changes in energy at different points [] Medical technology - Vertigo - problems in the Loss of hearing range as you get older - grandparents. ||
 * Mar 31 || Take up problems from # 47-57. Some of the troubles relate to determining the wavelength of the sound.
 * April 1 || Resonance class demo
 * 1) 35-43 ||
 * April 3 || Review of resonance - other applications - video and explanation
 * April 7 || Human Ear and Hearing

|| finish sound quiz 2, string and air column problems test next Tuesday - everything on sound ||  || Listing of major concepts for the unit test: 1. wave fundamentals - types, terminology; frequency, period, wavelength, and speed calculations; - interference of waves - constructive and destructive - doppler effect calculations 2. applications of waves - earthquakes (p&s waves, triangulation, travel time); - resonance (examples, factors that contribute to resonance) - sound (open and closed tubes, strings) - hearing and ear disorders (explain the energy transformations that take place; explain at least one medical disorder related to the ear) Last new topic for test - Sonar - what is it and how does it work in ships (submarines) and animals (bats, whales, dolphins) Difference between sonar and radar ||  || Begin new unit - electricity and magnetism 1.four fundamental forces - three associated with atoms and one that might not even be a force 2. atomic structure - location, charge, bonds 3. what causes electricity to pass through a circuit? All of these questions are based on a general knowledge of the periodic table and chemistry 3u ||  || 1. describe the main parts of an atom in terms of location, size, and charge 2. describe the two traditional models of the atom: plum pudding and planetary; are these models accurate? 3. describe the relation between the number of electrons in the outermost orbital of an atom and that atom's location on the periodic table 4. assuming you have heard of Rutherford's gold scattering experiment, explain the significance of the result First need to agree on what a series, parallel, and mixed circuits are. And we need to understand current flow (+) vs electron flow (-) - current is equal at all points in a series circuit - current into a branch is equal to the current out of a branch; current in each branch is split, sometimes equally - the sum of voltage (potential difference) drops in any path is equal to the voltage of the battery - voltage drop in any path of a parallel branch is equal || do the first side of this page || In a series circuit, every electron goes through the same path and through every load In a parallel circuit, electrons (and current) are divided among the different paths available; more electrons take the "path of least resistance" Voltage rules: sum of voltage increases (battery) equals the sum of voltage drops in any complete path; every electron in a circuit loses the same amount of energy, regardless of the path taken; the voltage drop in any section of a parallel branch is equal. Current rules: remember that current flows from + to -, while electrons flow from - to +. We use electron flow in this class. Kirchoff's laws for current tell us that: the current at any point in a series circuit is equal; the current into a junction or split is equal to the current out of a junction; the series current is split when it enters a parallel branch, sometimes equally.
 * April 8 || review of sound and waves, hearing and hearing problems
 * April 10 || Review for test - Tuesday
 * April 14 || Review questions for test - tomorrow - h[|ere is a link to the formulas] that you will have
 * Apr 15 || Test on sound and hearing ||  ||
 * Apr 17-21 || Easter Break ||  ||
 * Apr 22 || Beginning of Last Unit - Electricity and Magnetism
 * Based on what you have learned about atomic structure in chemistry class **
 * Apr 24 || Very few circuits are entirely series or parallel; most are a combination of the two.

Calculation for Resistance - R = V / I Introduction to Ohm's law, which allows us to calculate the current, voltage, and resistance both in an entire circuit and in an individual device. 1. for a single device, if we know two of resistance, voltage and current, we can calculate the third. 2. for an entire circuit, things are a bit trickier because we need to find the total (called Effective) resistance: - for a series circuit, the effective resistance is the sum of all the individual resistances - for a parallel circuit, the effective resistance is NOT the sum of the individual resistances. It can easily be shown that as you add more branches to a circuit, the resistance goes down. Think of the truck analogy: as you add more roads, even if the roads have toll booths, potholes, or protestors, more trucks get through than on a single road with only one of those obstacles. || second side of Kirchoff's laws handout || Can I replace the resistors in a series, parallel, or hybrid circuit WITH A SINGLE RESISTOR and achieve the same results? What happens to effective resistance when we add more resistors? - in series, as we add more resistors, the effective (or NET or TOTAL) resistance INCREASES and Re = R1 + R2 + R3 +... - in parallel, as we add more resistors, the effective resistance DECREASES and 1/Re = 1/R1 + 1/R2 + 1/R3 + ... We did three problems on the board - ask Jacob, Nathan, Matthew, or Andrew for the diagrams || Solving circuit diagrams do two of each
 * Apr 28 || Effective resistance in series and parallel circuits.

p 538 # 1-4 p 551 # 1-5 p 564 # 21 || Here is a link to the diagrams - ||   || Everyone was taught how to calculate the cost of electrical energy Cost of Electricity = # of kw used * # of hours * cost per unit (which is between 8-12 cents per kw*hr) in Ontario || finish diagrams on p 538, 551, 569#21 cost problems p 556#1-4 p 564 # 24 || Review of circuit diagram calculations - from the three sets of problems in the handouts New problems from the handouts || p 554 #1-3 p 564 # 15,16,18,19 || Review of power in electric circuits Power = rate of using electricity = V²/R = I²R = VI answer is in watts It is more useful to use kilowatts, since watts are a very small unit; in fact, household energy consumption is measured in kilowatt-hours, that is, 1000 watts used for one hour. The cost per kw-hr is between 8 and 12 cents in North America. Today we look at drawing circuit diagrams to solve specific problems || || || Tasers - video from [|CBS News] and written supplement We watched the first part of the video in class. Questions to answer: 1. explain how the body uses electricity to function 2. explain how a taser disrupts the electrical system in the body 3. explain/list any significant side effects of taser use 4. in your opinion, are tasers safe? Here's [|another report] from CTV News about at 11 year old who was tasered by police And here is a [|60 Minutes report] on taser safety - CBS ||  || Collect data on R, V, and I for electric devices in the school - using a rate of $0.12 per kw*hr, find the cost of running each device for one hour. Compare your results ||  ||
 * Apr 29 || Review of resistance calculations - finish circuit diagrams from yesterday.
 * May 1 || French trip students got caught up on circuit calculations - effective resistance and circuit analysis
 * May 5 || Review of University application process - www.ouac.on.ca
 * May 6 || Review of circuit calculations - here's a good online resource - [|the physics classroom]
 * May 8 || Quiz and Challenge problems for circuits || [[file:electricQuiz.pdf|Quiz1]]
 * May 12 || Resistance of the human body - application to taser use, specifically to the Robert Dziekanski death. The electrical nature of the human body and the use of high voltage to disrupt the natural communication system within the body.
 * May 13 || Work period for electricity quizzes and electric power consumption of devices in the school
 * May 15 || ===Energy Generation Projects - pick an energy source and a partner ===

1.A current flowing through a wire induces a magnetic field. In elementary school you created an electromagnet by wrapping wire around a nail or bolt and then connecting the ends of the wire to a battery. Although the nail or bolt makes the electromagnet stronger, the magnetic field is a result of current flowing through the wire coils. 2.A wire that passes through a magnetic field induces a current in the wire. This is the key idea for our discussion on electricity generation. Although modern technologies (solar and wind) don't involve the motion of a turbine or generator, most of the large-scale electricity generating plants use steam or water to spin a turbine. Your class presentation will explain how energy is converted and how electricity is produced. Application - building a small electric motor using a battery, a magnet, paper clips, and wire. Here is the website that I refer to [|http://scitoys.com/scitoys/scitoys/electro/electro.html#motor] Don't worry if your motor does not work on the first day. We will make adjustments to the design next week. ||  || - battery, insulated wire, paper clips, magnet, tape - to create a working motor. Key to this project is having an armature that rotates evenly and has half of the armature wire coated and half bare. ||  || Research day for energy presentations - we will present next week. Be prepared to show or demonstrate something as part of your presentation ||  || Exam Review - day 1 Next week we spend on presentations AND exam review ||  || We will do that tomorrow. I am giving a final exam in Grade 12 physics this afternoon. ||  ||
 * What energy transformations occur?
 * What is a key point in how electricity is generated?
 * Is it renewable or non-renewable?
 * Give a significant pro and/or con.
 * Propose ways to improve the sustainability of electrical energy production ||  ||
 * May 20 || Two key ideas in electromagnetism:
 * May 22 || Test on electricity - last test before exams ||  ||
 * May 26 || Simple motor building - use the instructions provided last week plus simple materials
 * May 27 || Hand out exam review sheets - we will do review topics over the next two weeks, but not every day.
 * May 29 || Hand back electricity unit tests
 * June 2 || Presentations and exam review ||  ||
 * June 3 || Presentations and exam review ||  ||
 * June 5 || Presentations and exam review ||  ||
 * June 9 || Today is a study day for you. A really good use of your time is making a list of all the concepts or problems that you need to get help with.
 * June 10 ||  ||   ||

timeline, Grading policies (most consistent, most recent, lates/zeros) Homework policies, quizzes, [|100 points of assignments] Some key ideas in physics - energy, invention, practical - difference between uniform and accelerated motion - difference between speed (scalar - just a number) and velocity (vector - also has a direction) - key quantities in the first unit: distance, speed, acceleration = all scalars displacement, velocity, acceleration = all vectors || Timeline and Course Syllabus || - calculation of speed ( = distance / time) - standard units for distance (m, km) time (sec, hr) and speed (m/s and km/hr) Introduction to problem solving - formula, at least one step, answer with correct units (units are very important in physics)
 * =**Today's Date**= || =**Class Topics and Notes Summary**= || =**Homework/Handouts**= ||
 * Sept 3 || How to succeed in this course - course syllabus and
 * Sept 5 || Outline of first unit -motion

Introduction to lab 1 - [|Carts and Collisons] (Next Class) || Chapter 1 Problems given info formula substitution answer with correct units || We need to make sure that the cart is heavy enough, far enough up the ramp, and at a large enough angle that the container travels more than a few centimetres. We want the data to have a reasonable range, rather than a very small range. ||  || that you changed. You chose between changing the mass of the cart, the distance the cart rolled, the angle or height of the ramp, and the mass of the container. For homework you must calculate your trial averages AND make one graph in Google. Don't make it too fancy and do NOT connect the dots. We never connect the dots on a graph in physics class ||  || complete with a good title, axes labeled, and units given Calculations of speed, distance and time - be careful when mixing and matching units We prefer to use the standard units in physics - metres, seconds, kilograms - so make sure you convert to those. || Homework P 7 # 1-4 complete solutions || Take up homework problems - we learn that method for solving problems when the work is easy; that way we know the process well when the problems are harder. Learn the process! New work with problem solving - work in standard units where possible. Using graphs to solve problems. Conversion from km/hr to m/s or other way around. Requirements for handed in lab - next class. Using Xuru.org to find the line (equation) that best fits the data. Look at the data and try to guess or calculate the equation. || p. 8 # 1-4 p 11-12 # 1 || work period for solving physics problems - focus on format. || complete solutions for p 29# 10, 11, 13, 14 16, 17, 20, 21 || presentation on vectors and scalars - handout calculation of distance or speed (both scalar quantities) and displacement and velocity (both are vectors) note that displacement and velocity always refer to the shortest distance between start and finish, not the actual path. Calculations of distance vs displacement and speed vs velocity - displacement and velocity are both vectors - measured "as the crow flies" - vectors include a direction, which is a rotation from North (0 or 360 degrees) Homework for Monday is handing in the two-page lab report. || vectorsAndScalars || Review of distance vs displacement and speed vs velocity - vector problems involving oblique triangles. Ex: car travels 60 km west and then 40 km north-west (315º), in a time of 1.5 hours. Calculate the distance, displacement, speed and velocity of the car. I want you to draw a (scale) diagram, but don't take your answers from the diagram; use the diagram to confirm your algebra and trig work Two options for adding vectors: - use the laws of sines and cosines - use vector components of right triangles || HW - a ship travels 35 km @ 130º, then 10 km @ 220º, and finally, 15 km @ 90º, in a time of 2.5 hours. Calculate the displacement and the velocity
 * 1) 28-29
 * Sept 9 || Whole class to collect data for the carts and collisions lab. Make sure you get a good baseline for your data - in step one.
 * Sept 10 || Finish data collection for lab. By the end of this class you will have two good sets of data - one set for each variable
 * Sept 12 || Discussion of lab results - for next class you must make and POST to your physics shared document BOTH graphs,
 * Sept 16 || Check graphs for completion, accuracy. Make recommendations for fixing things up or making things better.
 * Sept 17 || Review of homework problems, focus on format: start with formula, substitution, answer with correct units. [|Requirements for the lab due next monday]
 * Sept 19 || Questions about the lab or the homework?
 * Sept 23 || ** Quiz next class ** on first set of problem solving, some definitions/comparisons, units and unit conversion, vectors and scalars

answer: 46.5 km @ 130.5º || - if you are given a graph, draw a tangent line to the graph AT THAT POINT and measure the slope of the line - a tangent line is a line that touches a curve in exactly one spot (over a short distance). The handout in class shows how to calculate the slope (speed) at 5 points along a distance vs time curve. For the slope of tangents on distance-time graphs: - don't count squares - don't measure with a ruler - use the scale on the x and y axes If you are given a table of data, you will have to take the slope between points that are near the point in question Quiz on first few topics - motion, calculations, vectors - remember that quizzes are a chance for you to find out what you know and where you need to work. Quizzes NEVER count against you; in fact, they may even help your mark if they show a better understanding than your end-of-unit tests/projects/etc. || quiz 1 || Monty Hall problem - as an introduction to Thursday's activity on probability. Try [|this link] if you need to convince yourself that switching is always best. Review of using components to solve vector addition problems (displacement and velocity) additional practice problem: use components to solve the following: travel 100 km @ 290º, then 120 km @ 80º, finally 80 km @ 150º Last year's answer 65.77 km @ 102.5⁰ || [|probability]
 * Sept 24 || Instantaneous Speed - how do we measure the speed of an object when the speed is constantly changing - like in real life??
 * Sept 26 || Quiz due next class

[|probability assignment] || Important to choose an experiment where you get lots of data: - roll 10 dice and count the number that are 4 or less - roll 2 dice and keep track of the sum of the two dice - pick 10 cards from a deck and count the number that are face cards you will make two graphs for this experiment - explained in detail during class First graph is a distribution - it should look like a bell curve Second graph is the cumulative probability of your experiment - over dozens or hundreds of trials || review of dist/speed/time and displacement/velocity
 * Sept 30 || Probability assignment - we will collect data next class

p 29 # 22, 23 - graphs p 29 # 25, 27, 29 problems || part 1 of the lab is to look at the distribution of results - how many times did I get 3 face cards, 4 face cards, etc. This should give the normal distribution (bell curve) part 2 is to look at the cumulative probability of your experiment - as you do more and more trials, the probability of picking a face card should get close to 12/52 ||  || You need to finish the lab - one per group. One sheet that includes two complete graphs plus a paragraph that describes the experiment, what the expected result was, and how closely your results matched the prediction. When finished, work on two graphing problems || P 29 # 24, 25 || One more quiz to do in class today. Begin new unit on acceleration - none of this material is on the test so...how do we know that an object is accelerating? - we can try to measure it directly - we will use a ticker timer and a physics cart, and graph distance vs time (6 dots = 0.1 sec) - we can measure it indirectly - one way is with the coffee cup test, though this really measures the inertia of an object || Quiz 2 [|First Accel Problems] || Acceleration with a physics cart and a ticker timer - practice measuring points on ticker tape. Solving problems using average speed for acceleration problems - this method works, but perhaps there is a better way? What if we combine some of the formulas from last class? Kinematic formulas for acceleration problems: we will use: vf = vi + at d = vi t + ½ a t²  vf² = vi² + 2ad d = vf t - ½ a t² || Take up problems 1-3 from the handout do problems 4 and 5 by using a combination of formulas
 * Oct 1 || Collect data for probability assignment - reminders:
 * Oct 3 || Mr Guetter is absent today.
 * Oct 7 || Test **NEXT TUESDAY** - everything covered so far.
 * Oct 8 || Check problems 4 and 5 from the accelProbs handout - you need to work with two different formulas in each problem. In number 5 you need to use elimination or substitution to solve 2 equations with 2 unknowns.

then redo problems 4&5 with kinematic formulas || Using a ticker timer to determine the acceleration of a cart down a ramp. In groups of two, you will use a cart, a table, and a ticker timer to: - see that a cart rolling down a ramp accelerates - measure the acceleration using the ticker timer - make a graph of distance from start vs time for the cart - calculate the acceleration of your cart using kinematic equations - determine the relationship between height of ramp and acceleration (using the results from the rest of the groups) ||  ||
 * Oct 10 || Final review for test - what questions do you still have??
 * Oct 15 || ** Test on Unit 1 - whole class ** ||  ||
 * Oct 17 || Finish analysis and graphs for ticker timer acceleration lab - not to be handed in; just checked and compared to other graphs in class. ||  ||
 * Oct 21 || Check homework from ticker timer lab - what is the relationship between the height of the ramp and the acceleration of a physics cart?

Graphs for distance and speed of an object with uniform acceleration: 1. The general shape for distance vs time (accel vs decel) 2. The general shape for speed vs time for (accel vs decel)

Your homework is to complete the TWO data tables and FOUR graphs from the handout: a v-t and d-t graph for an accelerating object and a v-t and d-t graph for a decelerating graph. Answering the questions should be easy once you have the table and the graphs. || Accel Graphs Complete the handout on accel graphs || 2. Another way to find the distance an object travels while accelerating or decelerating is to calculate the area enclosed by the speed-time graph. The area can usually be divided into rectangles and triangles, and we can calculate those areas easily. || chapter2problems
 * Oct 22 || 1. Review of general shape for acceleration and deceleration graphs - always need to get general shape correct and label (at least) one non-zero point.

p 36 # 1-5 p 45,46 # 1-4 || Review of the shape of distance-time and speed-time graphs Introduction to video analysis of projectile motion - [|Tracker Software] In the next activity you will use a video camera to record and analyze the motion of a projectile - I will show you how the software works today, have you pick an activity next class, and gather the video footage and begin analyzing data later this week. The final product will be a **class presentation** by your group of three or four students. || New acceleration problems p 56 # 15, 18, 19, 23, 26
 * Oct 28 || Check homework from p 36, 45 - well done.

answers || Video each group with at least three different projectile paths Lab Analysis - use Tracker software to import the video, set the scale and origin, and track the object position frame by frame. The data will allow you to create three different graphs for the three throws: one of height vs time, one of horizontal distance vs time, and one of height vs horizontal distance. Mr Hunse can show you how to arrange the x-y data for the third set of graphs. In each graph, you will have THREE sets of x-y data. We will present this lab in groups during the week of Nov 11 || p 56 # 20, 22, 24 || Lab Analysis - use Tracker software to import the video, set the scale and origin, and track the object position frame by frame. The data will allow you to create three different graphs for the three throws: one of height vs time, one of horizontal distance vs time, vertical speed vs time. We will present this lab in groups after next week. Here is the list of requirements: [|Projectile Presentation] ||  || Review of what is expected for your group's presentation - see handout from last class New - graphical and algebraic solutions to acceleration problems || Algebraic Problems || Take up algebraid problem #1 using equations for Vf and D. Here are the graphs: To find the time when the speeds are the same, we get two equations for Vf (one for police, one for motorcycle); then we substitute and solve for time; then we can solve for Vf, the speed. To find the time at which the distances are equal, we get two equations for d (using vi t + ½ a t² - one for police, one for motorcycle); then substitute and solve for time; then solve for d, the distance. || Acceleration quiz 1 - online at [|classmarker.com]
 * Oct 29 || Planning / Design for data collection and analysis - all groups collected good, useful video
 * Oct 31 || Computer lab - use tracker software to analyze video. Demo in class, then work in library. You can download the software for use at home
 * Nov 4 || Review of what you've learned from the Tracker lab so far - origin, scale, plotting points, producing the required graphs.
 * Nov 6 || Next Monday you get half a class to prepare for the presentations, which will be on Tuesday. Today we finish the lesson on algebraic and graphical solutions to motion problems. By the end of the class, you should be able to solve accel/decel problems using graphs (estimate) and algebra (precise).

Here are your usernames and - change your password so the accounts don't get hijacked by people on the web || **Introduction to the Amber light problem** - this is just another application of the kinematic equations, but it relates to a very specific problem area for new drivers. The question in its simplest form is this: when the light turns yellow, can I safely stop OR safely go through the light? Or will I be in trouble if I choose the wrong option here? The amber light problem can be solved by using a number line to indicate two regions: a region in which it is safe to continue at the current speed, and a region in which it is safe to stop (including both the reaction and stopping distances). The safest intersections have overlap between these two regions - that is, there is a region in which you can either safely stop or safely go, so it doesn't matter which one your choose. For example, if the light is yellow for 4 seconds, your speed is 80 km/hr (22.2 m/s), your reaction time is 1 second, and your deceleration rate is (-) 5m/s², you should be able to calculate the following: - min distance to make it through at current speed = 88.9 m (for any distance < 88.9 m, you can continue) - reaction distance before braking = 22.2 m + distance while stopping vf² = vi² + 2ad gives 49.3 m for a total of 71.5 m So ... you can brake if you are more than 71.5 m away and you can stop if you are less than 88.9 m away, which gives a transition (or safety) zone of 17.4 m.  In the transition zone, you can either go through at the current speed OR safely stop; it doesn't matter which one you choose - both are right. And safe. And you can nicely draw this on a number line: ||   || -if we continue at the same speed, we use the formula for uniform motion: d = v*t -if we decelerate, we divide the problem into TWO parts: the reaction time (in which the speed remains the same) and the stopping distance, which is solved using vf² = vi² + 2ad. The reason we use the equation for vf² is that this gives the total distance required to stop, even if it takes longer than 3, 4.5, or more seconds. Plugging t and a into the distance formula just tell us how far we travel in a certain time, but doesn't tell if we have actually stopped in that distance. Again, I'm not accounting for the third option - speeding up when the light turns yellow - because I don't want to be the reason you start driving aggressively. I'll let someone else do that... Part 2 of the problem, using the same reaction time and the same deceleration rate: If you are traveling 60 km/hr and are 50 m from the intersection when the light turns yellow (3 seconds) -what should you do? can safely stop or continue -how large is the safety zone for this amber light? 50.1 m if you continue, 44.5 m required to stop, so the safety zone is only 5.5 metres, which is about 0.3 seconds at a speed of 60 km/hr. In the previous problem, the safety zone is about 17.4 m, which is 0.8 seconds (or so) - a much longer time. ||
 * Nov 11 || This is your class to prepare for the presentation of your Tracker Lab - use your time well. ||  ||
 * Nov 12 || Presentations of Tracker Lab - all groups did a great job.
 * Nov 14 || Review part 1 of the amber light problem. In terms of the calculations, here are the basics:

Hand in next class so that I can check your method of problem solving || collect paper copy of acceleration assignment - to check your problem solving method. Three ways of calculating the distance covered while accelerating - graphs, average speed, and kinematics formulas Accel 3 Ways handout - lays out each of the methods for determining the distance covered - and you get to practice each one. Review assignment for Thursday's test ||
 * Nov 18 || Check online quiz

|| This is a follow-up to our first unit lesson on vectors - in which we looked primarily at displacement vectors. Now we deal with problems in which the velocity of an object is affected by a velocity in another direction - for example: a boat or airplane affected by a current or wind. How do we calculate the resultant velocity of an object that is moving in two directions at the same time? Vectors. Ex: Boat heads directly across a [|river] while the current pushes the boat downstream. Can we calculate the actual speed of the boat and predict where and when it will reach the opposite shore? Ex: An [|airplane] wants to go directly north, but there is a wind blowing from the west. At what angle should the plane head to compensate for the wind and what will its speed be? Two dimensional motion problems can be solved by adding vectors - a tutorial to get you started is [|here] here are links to visual examples [] [] ||
 * Nov 19 || Review class for Thursday's test - 4 problems, all formulas provided. ||  ||
 * Nov 21 || Test - whole class - some need to finish on or before Monday's class. ||  ||
 * Nov 25 || Begin last topic for unit on motion - using vectors to describe motion in two dimensions.

p 64 # 1-3 p 65 # 1-3 p 67 # 1 || - if we ignore the wind or current, what is our NET (faster) velocity and where do we end up? - if we compensate for the wind or current, what is our NET (slower) velocity? Next time we will deal with (a few) problems that don't use right angles - do we have the tools to be able to solve these vector diagrams? || P 70 # 12-14, 16-18 || 1. if you do not account for the moving medium, the medium pushes us along and we end up off course. 2. if you take the moving medium into account, you need to compensate for it to stay on course. In both cases, you need to use trigonometry to solve for speeds, distances, and headings. In most cases, we deal with right angled triangles; however, you will need to use the law of sines or law of cosines from time to time as well. Two examples for today - these are harder than the typical problems, so if you can solve them, you're fine! 1. An airplane flies on a heading of 285 degrees at 600 km/hr but is affected by a wind blowing north at 60 km/hr. Find the actual velocity (speed and heading) of the plane. 2. A boat can travel 5 m/s and a river flows north at 2.5 m/s. The boat needs to cross a river that is 300 m wide, from west to east, and end up 50 m upstream from where it started. Find the heading that the boat needs to take so that the current pushes the boat on the correct course. || for homework:
 * Nov 26 || Review of river crossing and airplane navigation problems - there are two key calculations:
 * Nov 28 || Review of introductory concepts:

for problem 2, find the speed of the boat as it crosses the river AND the time it takes to cross. || New problem - boat heads upstream at 4 m/s at angle of 20 degrees, if the current pushes the boat downstream at 2 m/s, find the actual speed of the boat, the time to cross the 100 m wide river, and the distance you end up downstream. (3.8 m/s, 26.6 sec, 17 m) And another variation: boat and current speed are the same as above, river is 100 m wide, but now we want to land exactly 40 m downstream. At what angle do we aim the boat (relative to directly across)? (law of sines gives 27.6 degrees, so the answer is 6 degrees upstream from straight across)
 * Dec 2 || Today we finish the vector problems

- four fundamental forces (strong, weak, electric, gravity) these forces decrease in strength (from left to right), but increase in distance over which the force operates - this means that the strong force (which holds the atomic nucleus together) is incredibly powerful, but it only operates over very short distances; gravity is the weakest force, but it can operate over incredibly large distances - Newton's second law: an unbalanced force applied to an object will accelerate the object in the direction of the force. - this gives rise to the equation f = m*a where force is in Newtons, mass in kg and a in m/s² Gravity - the calculations used for gravity depend on whether the object is near the Earth or nowhere near the Earth. - if the object is near the Earth, we calculate the force with f = m*g where g is the gravitational field strength near Earth ( = 9.8 N/kg) - if the object is not near the Earth, we need to use a more general calculation (Newton's law of universal gravitation) || Homework - from handouts || Intro lesson on Radioactive decay and radiometric dating techniques A few things to take away from the discussion: - there are many different methods of determining the approximate age of a substance - the best or most reliable results occur when two different methods give the same result - the principle of uniformitarianism has strengths and weaknesses to it - radioactive decay curves all have the same shape; the difference is in the time scale - hundreds, thousands, millions, billions. And that's where some of the debate is. - I am convinced that the Bible and the world tell us the same things about God and the creation; I am committed to believing the Bible and honouring the results of scientific inquiry. I think we run into problems when we force one to match the other - see [|Article 2 of the Belgic Confession] ||  || Now we start another unit - Forces and Gravity. This unit will expand on the idea of motion by looking at forces as the cause of motion. - four fundamental forces (strong, weak, electric, gravity) these forces decrease in strength (from left to right), but increase in distance over which the force operates - this means that the strong force (which holds the atomic nucleus together) is incredibly powerful, but it only operates over very short distances; gravity is the weakest force, but it can operate over incredibly large distances - Newton's second law: an unbalanced force applied to an object will accelerate the object in the direction of the force. - this gives rise to the equation f = m*a where force is in Newtons, mass in kg and a in m/s² Gravity - the calculations used for gravity depend on whether the object is near the Earth or nowhere near the Earth. - if the object is near the Earth, we calculate the force with f = m*g where g is the gravitational field strength near Earth ( = 9.8 N/kg) - if the object is not near the Earth, we need to use a more general calculation (Newton's law of universal gravitation) || p 142 # 1-3 p 144 # 18, 20 || 1. Inertia - an object at rest remains at rest and an object in motion remains in motion, unless acted on by an unbalanced force 2. Acceleration - an unbalanced force causes an object to accelerate in the direction of the force 3. Reaction - all forces act in pairs that are equal and opposite; for every action there is an equal and opposite reaction Free-body Diagrams - a dot that represents an object; arrows represent the vectors (forces, in this case). The goal is to reduce a problem to an object with ONE FORCE in ONE DIRECTION. We agree to call any reaction force provided by a surface the NORMAL force = Fn. This is to balance the force of gravity on objects, for example, when a coffee cup is at rest on a table. There are two forces, Fg and Fn, and they point in opposite directions, resulting in a net force of zero. Newton's laws - review of the three laws, with focus on the second law. If an unbalanced force acts on an object, the acceleration is given by f=m*a, where m is the mass of the object, f is the force (push or pull) in Newtons, and a is the acceleration in m/s². || P 142 Q 6,7,8 p 144 Prob 21,22 || - if we change the mass without changing the force, the acceleration is proportional to 1/m - if we change the force without changing the mass, the acceleration is proportional to f Hard problem - find the change in acceleration if we make the mass 2/3 and the force 3/2 of the original. (answer is the accel is 9/4 times as large) || p 144 # 18-21 || Review of free-body diagrams. We draw an object as a dot and label all forces as vectors. We use a simple notation for common forces: Fg for gravity, Fn for the upward force that opposes gravity, Ffr for friction, and so on. We learned that there is a connection between the force applied to an object and the acceleration that a mass experiences - and this is given by Newton's second law: Fnet = m * a || P 144 # 22,23,25,26,27,28 || If tomorrow is a snow day, we will postpone our unit test until Next Monday.
 * Forces Introduction ** :
 * Dec 3 || Connection to math class - exponential growth and decay = radiometric dating
 * Dec 9 || We start today with the homework questions I assigned last class - you were to ask someone at home not just what they thought of the idea of an old or young Earth, but if they favoured one approach over the other.
 * Forces Introduction ** :
 * Dec 10 || Review of forces - introduction to Newton's three laws of motion
 * Dec 16 || Review of Newton's Laws of motion, the calculation of net force and acceleration, and the application to kinematic problems. We worked through the six problems on the worksheet that we started last class. || [[file:NewtonsLawsAndFBD.pdf|N's laws and FBD]] ||
 * Dec 17 || General relationship between mass, force, and acceleration in Newton's second law.
 * Dec 19 || Forces - answers the question "what causes things to move" clip from "Chuck" -[]
 * Jan 6 || Here is a quiz for you to work through - we have not had time to do Force of Gravity calculations and Newton's Law of Universal Gravitation, so skip those questions. We will complete that topic next week.

Review of Free-body diagrams, net force, acceleration, and kinematic calculations - the force of gravity on an object is given by Fg = mass* g, where g = 9.8 N/kg or m/s² - draw FBD, calculate net force, solve kinematic problems.
 * for objects accelerating upward, we must always account for gravity in determining the net force
 * air resistance is not a constant amount; in general, it increases as the speed of an object increases, to the point where the air resistance equals the downward force of gravity (terminal velocity). You can see this more clearly if you drop a rock in water. || [[file:guetter/FGNquiz.pdf|take-home quiz]]

C-3 the answer is 612.5 N, not 1089 N || Review for Airplane/River problems - see Nov 25 - Dec 2 Forces, Free Body Diagrams, Newton's Laws - see Dec 10 - 19 - focus on understanding the three laws AND on applying the second law to calculating acceleration and solving kinematics problems ||  || Review for Test: 2 problems on airplane/river problems, one with non-right-angled triangle 2 problems and 2 short answer questions on forces, FBD, Newton's laws of motion 1. plane flies North @ 450 km/hr, wind blows East @ 80 km/hr. Find the velocity if we do not compensate for the wind. Find the heading the plane needs to take in order to fly directly North. 2. A boat travels 15 km/hr @ 270 degrees. The current flows 5 km/hr @ 40 degrees. Find the velocity of the boat (both speed and direction) 3. Calculate the net force and acceleration after drawing a FBD with 3 vectors for a 10 kg ball pushed with a force of 30 N (East) 4. A 1000 kg car rolls to a stop from an initial speed of 60 km/hr over a distance of 200 m. Find the rate of deceleration and the net force acting on the car (the braking force or frictional force from the road) || Answers: 1. 457 km/hr @ 10 deg 350 deg 2. 12.4 km/hr @ 288 deg 3. 3 m/s/s 4. 0.69 m/s/s, 694 N || then work on Newton's law of universal gravitation ||  ||
 * Jan 7 || Another snow day, so our test will be moved to next Monday or Tuesday.
 * Jan 9 || Review of Vectors, Newton's Laws of motion, free-body diagrams, calculations of force, mass and acceleration, connection to the kinematic equations, proportions.
 * Jan 13 || last minute review for test.
 * Jan 14 || **Test** on motion in two directions (rivers and airplanes), free body diagrams, Newton's laws of motion, and kinematic calculations ||  ||