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Chapter 2 Section 6

 * What do you See? (12/13/10)**
 * Someone on a chair with wheels pushing against a house and being able to push himself back


 * What do you Think? (12/13/10)**
 * Pretend that you have just met somebody who has never jumped before. What instructions would you provide.
 * I would tell him to bend his knees and exert force downward. That way since he is pushing off the ground, he will be able to move himself up and jump!


 * Physics Talk (12/14/10)**


 * Newton's Third Law- for every applied force, there is an equal and opposite force. The two forces always act on different objects
 * In the example, the student pushed on the wall, and the wall "pushed" on the student
 * If you exert force on something, it will exert the same amount of force
 * Free-Body Diagram- the diagram that shows the forces acting on an object
 * Center of Mass- the point at which all the mass of an object is considered to be concentrated
 * Newton's description of the Third Law of Motion
 * If you push or pull something, that something pushes or pulls back on you with an equal amount of force in the opposite direction
 * Forces always come in pairs


 * Checking Up (12/14/10)**

1. Describe Newtons' Third Law of Motion? 2. What is the opposite and equal force to gravity 3. What does a free-body diagram illustrate?
 * For every force, there is an equal and opposite force
 * upward gravity
 * the forces acting on an object


 * Physics To Go (12/15/10)**

1. When a person throws a shotput, does it exert a force on the persons hand equal and opposite to the one exerted on it? 2. When you sit on a chair the chair pushes up on your body with same force you push. How does it know how much to? 3. You have weighed yourself on a bathroom scale, how does it work 4. Compare the force of a bat on the ball and ball on the bat. 5. Compare the force of a linebacker hitting a small running back. 6. Identify the force active when a hockey player hits the boards on the side of a rink. 7. Why do baseball players prefer to wear gloves when catching a ball 8.
 * Yes, because every action has an equal or opposite reaction.
 * According to Newtons Third Law, for every force there is an equal and opposite force. The amount of force you put on the chair, is the amount it will put on you.
 * Spring with needle attached calibrated.
 * It is the same force for both, but the bat might not be able to handle it because the ball has a higher speed; therefore, it breaks.
 * The running back will have a higher acceleration, but the same force. The Linebacker has a greater mass and the force the linebacker creates will be more evident
 * Normal force of player to board and board to player. Weight of player to earth and Boards to earth. No Friction
 * Because the force the ball creates is the amount of force the player is going to have to create on the ball and if he doesn't wear gloves his hands will really hurt.
 * a. Make an imaginary voice-over for a sport using Newton's Third Law.
 * Here goes the Running Back, passes the first, the second, and the third defender. OH WAIT! The Linebacker just tackled him and brought him down. The force created by the Linebacker brought the running back down, but was also the same force exerted on the the Linebacker. The Running Back goes down, with the force of weight of the player to the earth, the normal force of the player and the ground apparent.
 * b. Can deflection of the ground produce a force?
 * A deflection of the ground can produce a force if you were to fall. During the fall, you would be pulling up the force from the ground while pushing down the force of your own. I would make this more exciting by showing a quarterback getting sacked and explaining it in action


 * What do you Think Now? (12/15/10)**

Pretend that you have just met somebody who has never jumped before. How would you tell them to do it?
 * I would tell them to apply force on the ground because according to Newton's Third Law a force has an opposite and equal force. That means if they applied force to the ground, the ground would apply the same amount of force on them and they would be able to jump.

Chapter 2 Section 7

 * What do you See? (12/15/10)**
 * A man is pulling a shoe on ice and its easy.
 * A man is pulling a show on sand and its hard.


 * What do you Think? (12/15/10)**
 * Why do some sports require special shoes
 * Because you need a different amount of cushioning, friction, and angle in your shoes in order to perform different tasks
 * Why would different features on a shoe be useful to different sports
 * Because they would allow the athlete to perform better under the circumstances of the level they are playing on and the conditions.


 * Physics Talk (12/15/10)**
 * Normal Force- Perpendicular to the object
 * Force is equal strength and in opposite direction of the shoe's weight
 * Coefficient Sliding Friction- symbolized by greek letter m and is defined as the ratio of two forces
 * greek m = force of friction/normal force
 * does not have any units of measurement because it is a force divided by a force
 * usually expressed in a decimal


 * Checking Up (12/15/10)**

1. Why is the force of friction equal to the force being read on the scale? 2. Why does the coefficient of friction have no units? 3. What determines the coefficient of friction?
 * Because the only thing holding the shoe from being dragged is friction. If the surface was frictionless, there would be no force needed in order to move the object
 * Because it is a force divided by a force
 * the kind of surface that is acting on the object


 * Physics To Go (12/16/10)**

1. Think of a sport and a changing weather condition that would cause an athlete to want better footing. 2. Describe a sport wear an athlete wants as little friction as possible and makes his shoes do that. 3. If an athletes basketball shoes provide the perfect amount of friction, how can she be sure that it will be the same on other courts? 4. Tennis players play on three different surfaces, do you think they do or don't have different shoes? 5. A cross country skier who weighs 600N chose ski wax that provides mu = .03. What is the minimum amount of horizontal force, perhaps from a tailwind that would keep the skier coasting constant speed? 6. A vehicle with a mass of 1000 kg had an accident. Tires had mu = .55. Skidded for 6 seconds. Claimed to be driving 29 m/s. 7. Do the forces of water and air resistance change when speed changes? 8. Is there a maximum acceleration when you start off on a track? 10. Explain why friction is important to running. Why are cleats used in football, soccer, and other sports? 11. Choose a sport and describe an event in which friction provides a significant role.
 * Soccer. In soccer an athlete wants a shoe with extra traction and friction because of the constantly changing weather conditions. Rain, Snow, and Dryness are all weather factors in soccer, so to treat that, a soccer player wears cleats to be able to dig into the dirt and prevent slipping
 * Ice skating requires no or little friction. An athlete wants to be able to glide across the ice and gain speed without the ice causing them to stop. For that they use extremely sharp blades so they can prevent friction on the ice.
 * She can't be sure. If she wanted to find out she would see if the material on her home court and the away court are the same. If she wanted to go extremely in detail she could measure the friction on the home court with a scale we use in class and on the away court and if its the same then she's fine.
 * They do have different shoes because the surfaces are different and provide different frictions. That means they need the different shoes to perform on the other surfaces
 * The minimum amount of Horizontal force would be 18N.
 * What is the weight of the vehicle?
 * 9,800 kg
 * Find the value of the frictional force
 * 550 N
 * Use the frictional force to find the acceleration
 * -4.83 m/s squared
 * Calculate the change in speed that the acceleration would produce?
 * 28.98 m/s
 * Use the change in speed to find the original speed of the vehicle when the breaks were applied?
 * The driver claimed that he was driving at 29 m/s before the accident happened. To my findings and conclusions, he is stating the truth. There was 550 N of friction and -4.83 m/s squared of deceleration in the time span of 6 seconds. His initial speed that means is the acceleration multiplied by the time and that is about 29 m/s; therefore, he is not lying.
 * I think it does, the faster you go, the more resistance you face. A good example is when I was in my car and it was really windy heading towards my car. My mom tried to increase the speed of the car only to be met with more resistance.
 * I think that friction does affect acceleration. It is however hard the shoe can grip the floor. Maximum friction limits acceleration.
 * Friction is important because it provides traction and allows the player to not slip whilst playing the sport. Cleats are used so the athlete is able to not slip while running and also be able to make more accurate stops and turns.
 * And here is Tiger Woods setting up for the putt, he is 20 feet away and this will be a big score if he makes it. He hits the ball... OH! the friction of the grass on the ball is too much and the ball does not make it in the hole.


 * Physics Plus (12/20/10)**




 * What do you Think Now (12/22/10)**

Why do Some sports require special shoes? Why would different features of a shoe be useful to different sports
 * Because in different sports, a different amount of friction is required to play them. For example in soccer, the surface might be slippery at times. Cleats would be needed to keep you from slipping. In Ice Skating, athletes want to reduce the sliding friction there and they do so by putting sharp blades on their skates
 * Because as stated above, the friction of surfaces played on is different. In basketball you want to have more sliding friction so you buy shoes with good traction. This will allow you to maneuver quickly and be able to turn and change position quicker. It baseball, an athlete that needs to sprint to a base wears cleats to provide great traction with the ground that gives him a push off the ground easier.

Chapter 2 Section 8

 * What do you See?**
 * Person wanting to pole vault to the roof party
 * Changing his horizontal speed into height


 * What do you Think?**
 * He might not be able to vault with an 11 m pole over a 12m bar because the pole is unmanageable and it won't convert his horizontal speed as well as a smaller pole would
 * I think speed, acceleration and horizontal force limit a pole vaulters height


 * Physics Talk**


 * Law of Conservation of Energy
 * a force can change the position and speed of an object in a way that allows the position and speed to change back
 * Kinetic energy is the energy associated with motion
 * Gravitational Potential Energy is the energy an object possesses because of its vertical position from Earth
 * Potential Energy is the energy associated with position
 * Law of Conservation of energy
 * energy cannot be created or destroyed; it can be transformed from one form to another, but the total amount of energy remains constant
 * Energy and Work
 * work- the product of the displacement and the force in the direction of the displacement (physics quantity that equals the force multiplied by the distance)
 * Conservation of Energy in the Pole Vault
 * Elastic Potential Energy is the energy of a spring due to its compression


 * Checking Up**

1. What is required for the energy of an object to change? 2. From where does the penny that is launched in the air get its energy? 3. From where does the pole vaulter get the energy needed to bend the pole and rise over the bar? 4. What are the units for Energy?
 * A force is required for a change in energy.
 * From a ruler that has elastic potential energy.
 * The vaulter's kinetic energy is used to catapult him with an initial speed upward and once he is at the top, Gravitational Potential Energy remains
 * Joules


 * Investigate**

1. Design an experiment to test one of the variables and its effect on the height of the penny. Remember, you can only change ONE variable at a time.
 * a. What will you be able to conclude as a result of your experiment?
 * If the mass affects its height
 * b. What data will you record?
 * Height reached, Mass of coins, Average
 * c. What tools did you use to make your measurements?
 * Meter Stick, Scale

Data:
 * Penny (2.51g)
 * Trial 1: 80 cm
 * Trial 2: 84 cm
 * Trial 3: 86 cm
 * Average: 83 cm
 * Dime (2.29g)
 * Trial 1: 90 cm
 * Trial 2: 87 cm
 * Trial 3: 91 cm
 * Average: 89 cm
 * Quarter (5.70g)
 * Trial 1: 44 cm
 * Trial 2: 43 cm
 * Trial 3: 49 cm
 * Average: 45 cm


 * Physics To Go**

4. Why does the pole alone not determine the limit of the vaulting height? 5. The temperature of poles increase slightly as they flex. Use the law of conservation of energy to explain how this would affect performance? 6. KE = GPE. 1/2mv(sq) = mgh. 1/2(v)(sq) = (9.8)(4.55). = 9.44 m/s 7. How did Sergei's Speed compare with Emma's? KE = GPE 8. A 2.0 kg rock is dropped off a 100m high cliff. 9. A bow is strung with a bowstring that has a spring constant k of 1500 N/m 10. An exercise spring has a constant of 315 N/m. 11. A toy car is released and slides down a ramp 12. The Unit of energy is a joule 13. A high diver jumps off the diving board... 14.A volleyball player is setting up a ball and hitting it up directly with her hands, Describe the energy transformation 15) Announcers make-over for baseball. 16) Describe a sport
 * It is not the length that determines the vaulting height, it is rather the speed you are going before.
 * At first, the poles energy increases because the vaulter is doing work on the pole with Kinetic and then Elastic Energy. When the pole straightens, it will decrease in temperature as the vaulter increases his/her gravitational potential energy
 * 1/2mv^2 = mgh
 * 1/2v^2 = (9.8)6.14
 * v=10.97 m/s
 * Sergei's speed is higher than Emma's speed.
 * GPE = KE. mgh = 1/2mv(sq). gh = 1/2(v)(sq)
 * EPE = KE. 1/2kx(sq) = 1/2mv(sq).
 * EPE = W. 1/2kx(sq) = W. 1/2kx(sq) = F x d.
 * GPE = EPE. mgh = 1/2kx(sq).
 * A. Because F, which is measured in N = m which is measured in kg, times a, measured in m/s^2, that means 1N = 1kg x 1m/s^2
 * B. GPE=mgh ; (kg)(m/s^2) ; 1kg x 1 m/s^2 = J
 * KE=1/2mv^2 ; 1/2(kg)(m/s)^2 ; 1kg x 1 m/s^2 = J
 * EPE = 1/2kx^2 ; 1/2[(kg)(m/s^2)/m]m^2 cancels out to 1kg x 1 m/s^2 = J, the same way GPE = kx^2 does
 * EPE > KE > GPE > KE
 * W = KE = GPE.
 * Here's the Pitch, OH! It is hit by the bat which does work which is made into kinetic energy until reaching the highest point. The balls energy transforms into gravitational potential energy and the net and ground make the ball come into rest.
 * In soccer, the ball is moving at an increasing speed, with its kinetic energy, then the ball is kicked up so work is done on the ball, at its maximum height the ball has GPE.


 * What do you Think Now?**
 * The person's speed is a very important factor in the height. The speed is what matters, not the length of the pole. The more velocity you having the more kinetic energy which makes a larger gravitational energy. Speed, the deflection of the pole, and their height limit the height a pole vaulter can go.

Chapter 2 Section 9

 * What do you See?**
 * Ice Skater Gyrating to the helicopter
 * Person in Heli timing the persons time in air (hangtime)


 * What do you Think?**
 * Does the hang time of some athletes defy the pull of gravity?
 * I don't think so because if you defy the laws of gravity then technically the law can't be one anymore
 * Does a figure skater defy it to be able to do a Triple Axel
 * No, I think the skater just needs to be fast with the amount of time they have in the air.


 * Investigate Section 9**

2. Count the number of frames during which the skater is in the air? 3. Each frame is 1/30 second. Calculate. 4. Did he hang in the air to defy gravity at all? 5. Repeat with the basketball player 2. Number of frames? 3. Calculate seconds? 4. Did he hang in the air to defy gravity
 * 20 frames
 * 2/3 of a second
 * It seems he is hanging in one general height at the maximum part of his jump
 * 31 frames
 * about 1 second
 * No, and it didn't seem like it either because his jump was more vertical

1. What is the sequence of events in the jump? What types of energy are present at each stage? 2. What would you need to know in order oto measure the force needed to jump to a certain height? Design an experiment to measure the force of your push off the ground 3. After getting permission, run your trials. 4. When you have calculated the force, bring your work up to your teacher. Have the jumper, use the force platform and measure the actual force. 5. How did your calculation compare to the measurement? 6. Create a poster showing clear calculations. When you are done, hang it up and be prepared to present your findings.
 * 1. Bend your knees
 * 2. Unbend knees
 * 3. Get in air
 * 4. Land back down
 * What will you be able to conclude as a result of your experiment?
 * The force it takes for me jump
 * What data will you record?
 * Height (.38m) and GPE (300.8 Joules) and Work (F * .2 m)
 * What tools will you use to make your measurements?
 * Data Studio Scale and Meter Stick
 * How will you analyze your data?
 * Data Studio in the form of a line graph
 * Discuss your design with the teacher. Get approval before continuing.


 * Calculations:
 * W = GPE
 * F * d = mgh
 * F * .2m = (85.27)(9.8)(.38m)
 * F = 1,587.73 N
 * Correct Calculation: 2020.85
 * Percent Error: 27%


 * Physics Talk**


 * Energy can neither be created nor destroyed, but assume different forms
 * KE
 * GPE
 * EPE
 * W
 * in ready position about to jump, you have EPE from contractions in muscles.
 * launch position has both GPE and KE
 * energy of all positions of a jump are equal
 * the greater the peak position, the greater the GPE
 * potential energy from height jumping would provide kinetic energy when you land. when going down, you continue to have kinetic energy bc you would be losing

1. Where does energy come from that allows jumpers from the ready position to the launch position? 2. In the launch position, what types of energy will the student have? What type of energy will the student have at the peak of the jump? 3) What are three other types of energy besides potential and kinetic?
 * Checking Up**
 * Contraction of Leg Muscles (EPE)
 * The student has both GPE and KE. Peak of jump - GPE.
 * light, chemical, and sound


 * Physics To Go**

1. Calculate the work of a male figure skater does when lifting a 50 kg female a vertical distance of 1 m in a pairs competition. 2. Describe the energy transformations during a bobsled run. 3. Suppose that a person who saw the video of the basketball player used in the Investigate said, "He really can hang in the air. I've seen him do it..." How might you go about to see if the person is correct. 4. If someone claims that a law of physics can be defied or violated, should they be required to provide evidence, or the person trying to disprove them? 5. Identify and discuss two ways in which an athlete can increase his or her maximum vertical jump 6. Calculate the amount of work, in joules, done when a: 7. How much GPE will things have above? 8. List how much kinetic energy, in joules 9. How much work is done on a go cart if you push it with a force of 50.0 N parallel to its path and move it a distance of 43 m, ignoring any friction that may exist?
 * W =GPE
 * F * d = mgh
 * F * 1 = (50)(9.8)(1)
 * F = 490 J
 * Player does work on the sled by pushing it to start
 * There is kinetic energy on the sled when its running
 * When the break is applied, there is work being done
 * We can split up the clip in frames and determine whether he did actually hang in the air.
 * I think the person that's making the claim should have to prove it because he wants to change a law of physics. He is also making a different claim, and to do that, you can't just throw a random one out there
 * If they increase the force they put on the ground when bending their knees, they could shoot up higher into the air
 * a. 1.0 N weight is lifted a vertical distance of 1.0 m.
 * W = F * d
 * W = 1 * 1
 * W = 1J
 * b. 1.0 N weight is lifted a vertical distance of 10 m
 * 10J
 * c.
 * 10J
 * d.
 * 10J
 * e.
 * 10J
 * Same as number 6
 * Same as number 6
 * F *d
 * 50 * 43 =
 * 2,150 J

11. A net force of 30.00 N acts on a 5.00 kg wagon that is initially at rest 12. Assume you do 40,000 J of work by applying force of 3200 N to a 1,200 kg car 13. A baseball is traveling at 40 m/s. How much work must be done to stop the ball? 14. A boat exerts a force of 417 N pulling a water skier from rest. Over what distance was this force exerted 15. Describe energy flow in pole vaulting. 16) Describe energy flow in Trampoline: 17) Describe energy flow of a skier 18) The player sets up for the free kick. He gathers Kinetic Energy by running at the ball and gives it a kick. The ball soars into the air and has acquired GPE now. It's still traveling and GOAALLLL!!!!
 * a. What is the acceleration of the wagon
 * a = F/m
 * 6 m/s sq
 * b. If the wagon travels at 18.75m, what is the work done on the wagon
 * 563J
 * a. How far does the car move the time you are doing work on it?
 * W = F x d
 * 40000 = 3200 x d
 * d = 12.5 m
 * b. What is the acceleration of the war
 * W = KE
 * 40000 = 1/2mv^2
 * 40000 = 1/2(1200)v^2
 * 66.67 = v^2.
 * v = 2.7 m/s sq
 * KE = W
 * 1/2mv^2 = W
 * 1/2(.15)(40)^2 = W
 * W = 120 J
 * W = KE
 * F x d = 1/2mv^2
 * 417d = 1/2(64)(15)^2
 * d = 17.3 m
 * Pole vaulting:
 * running, pole on ground bending, maximum height, landing, collapsing... sum is always the same, when the cushion collapses most of the energy is now work (the numbers could still be spread amongst the different types of energy).
 * Trampoline:
 * maximum height, landing on trampoline, lowest point on trampoline....sum is always the same (the numbers could still be spread amongst the different types of energy)
 * Skier:
 * top, middle, and bottom of a slope.... the sum is always the same (the numbers could still be spread amongst the different types of energy)


 * Physics Plus**

1. Roller-coaster... 2. Ball... 3. Motorcycle...
 * KE = GPE
 * 1.2mv(sq.) = mgh
 * 1/2v(sq.) = gh
 * 1/2v(sq.) = 196
 * v(sq.) = 392
 * v = 19.8 m/s
 * EPE + GPE = KE
 * 1/2kx(sq.) + mgh = 1/2mv(sq.)
 * GPE + W = GPE + Wout + KE
 * 200(9.8)(.025) + = (200)(9.8)(h) + + 1/2(200)(40(sq.))


 * What do You think Now?**


 * An athletes hang-time does not every defy gravity. If you split his jump in frames and analyze them, you will see that he/she is not actually ever in the same height in the air. Even a world class figure skater cannot defy gravity to do her jump, she just needs to build up more kinetic energy and do the jump faster before she has to land.