Ch2_LynchM

= Megan Lynch's Wikilog - Period 8 CP Physics - E. Burns - 2010 =

Section 1
There was a family riding home in two limos from a wedding and a drunk driver hit one of te limoswhich also caused te limo behind to crash as well. The family was was severely injured but five and seven year old girls were killed in the crash because they were so small in such a large car. The five year old got stuck in the wreckage while the seven year old was decapitated by her seat belt because she was buckled in and a asleep.
 * Homework**

I see boys playing soccer and one kicks the bal right over the goal and one the ball goes almost nowhere.toc
 * What do you see? **

Because of how hard they pushed the first time and the flat ice It had been pushed and keeps rolling because it is round
 * What do you think? **

1.c) 6.76m  e) 6.76 2.a) 6.70 m b) I think with more of an incline the momentum will carry him not as high as before 3. a) 6.76 close because I did not move the ramp that much b)??? 4. a) 6.76 b) 6.76 5. a) no b)??? c) It's equal <span style="font-family: Arial,Helvetica,sans-serif;">d) Once the momentum runs out
 * Investigate**

<span style="font-family: Arial,Helvetica,sans-serif;">Newton's first law of motion, Galileo formed the law of inertia: Inertia is the natural tendency of an object to remain at rest or to remain moving with constant speed in a straight line. After Galileo, people thought about how moving objects might continue to move forever unless a force, a push or a pull, stopped them. In the absence of an unbalanced force, an object at rest remains at rest, and an object already in motion remains in motion with constant speed in a straight-line path. "Running starts" take place in many sporting activities. In sports, where the objective is to maximize the speed of an object or the distance traveled in air, the prior motion of a running start is very important.
 * <span style="font-family: Arial,Helvetica,sans-serif;">Physics Talk **

<span style="font-family: Arial,Helvetica,sans-serif;">1. The natural tendency of an object to remain at rest or to remain moving at a constant speed <span style="font-family: Arial,Helvetica,sans-serif;"> in a straight line <span style="font-family: Arial,Helvetica,sans-serif;">2. In the absence of an unbalanced force, an object at rest remains at rest, and an object already in motion remains in motion with constant speed in a straight-line path. <span style="font-family: Arial,Helvetica,sans-serif;">3. Changing direction <span style="font-family: Arial,Helvetica,sans-serif;">4. Friction <span style="font-family: Arial,Helvetica,sans-serif;">5. The heavier one <span style="font-family: Arial,Helvetica,sans-serif;">6. Changes the perspective
 * <span style="font-family: Arial,Helvetica,sans-serif;">Checking up **

<span style="font-family: Arial,Helvetica,sans-serif;">**Physics to Go** <span style="font-family: Arial,Helvetica,sans-serif;"> <span style="font-family: Arial,Helvetica,sans-serif;">

The keep moving because there is very little amount of friction top stop or slow them down <span style="font-family: Arial,Helvetica,sans-serif;">It continues to move because of the speed it was kicked. The ball will stop unlike the ice skater because of the large amount of friction on a soccer field
 * What do you think now?**

1. Curling is a sport in which players slide stones across a sheet of ice towards a target area<span style="font-family: Arial,Helvetica,sans-serif;">, There are people the follow in front of the curling stoom with brushes to insure there is few friction as possible. The object in motion stays in motion for a while because there is so little friction on the ice. http://www.curlingbasics.com/
 * <span style="font-family: Arial,Helvetica,sans-serif;">Inquiring Further **

Section 2
<span style="font-family: Arial,Helvetica,sans-serif;"> A boy and a dog walking slowly. There is also a snail that is moving faster than both of them. The boys foot prints show small strides which shows how slow he is walking. In the second picture the boy is running. The dog also is running and the boy seems to be catching up to him. His strides are also longer which makes him move faster.
 * <span style="font-family: Arial,Helvetica,sans-serif;">What do you see? **

<span style="font-family: Arial,Helvetica,sans-serif;"> The 100 mi/h and 45 m/s shows how fast the ball in moving compared to the ground. The momentum and force from the player winding up and throwing the ball is how fast the ball is going to go.
 * <span style="font-family: Arial,Helvetica,sans-serif;"> What do you think? **

<span style="font-family: Arial,Helvetica,sans-serif;">1. a) Equal space apart <span style="font-family: Arial,Helvetica,sans-serif;">b) Equal farther apart <span style="font-family: Arial,Helvetica,sans-serif;">c) Equal closer together <span style="font-family: Arial,Helvetica,sans-serif;">d) They would get farther apart
 * <span style="font-family: Arial,Helvetica,sans-serif;">Investigate **

<span style="font-family: Arial,Helvetica,sans-serif;">6. a)

<span style="font-family: Arial,Helvetica,sans-serif;">7. a) the amount you move should be equal to how fast you are going the whole time you were walking <span style="font-family: Arial,Helvetica,sans-serif;">b) No, but it was very close. They were all around the same height other them where I assume I took a step; those were farther apart

<span style="font-family: Arial,Helvetica,sans-serif;">8.

<span style="font-family: Arial,Helvetica,sans-serif;"> Speed and acceleration can bee seen through the ticker timer. Constant speed: Distance between ticks was equal. Slow, constant speed: Distance between ticks was shorter than when you traveled faster. Fast, constant speed: Covering more distant than traveled slowly. When accelerating: distance between the dots on the tape was not equal. When gradually accelerating: distance between dots gradually got longer. When gradually decreasing speed: distance between dots gradually got shorter. Average speed: distance traveled divided by the time taken to travel that distance. Average Speed = distance traveled / time elapsed. Instantaneous speed: Speed at that moment. Calculating Acceleration: When an object changes its speed. Acceleration = change in speed / time interval
 * <span style="font-family: Arial,Helvetica,sans-serif;"> Physics Talk **

<span style="font-family: Arial,Helvetica,sans-serif;">**Checking Up** <span style="font-family: Arial,Helvetica,sans-serif;"> 1. a) Constant speed: Distance is equal between the dots <span style="font-family: Arial,Helvetica,sans-serif;"> b) Positive Acceleration: Distance between the dots got longer <span style="font-family: Arial,Helvetica,sans-serif;"> c) Negative Acceleration: Distance between dots got shorter <span style="font-family: Arial,Helvetica,sans-serif;"> 2. Vav = d/t <span style="font-family: Arial,Helvetica,sans-serif;"> Vav = 400 / 50 <span style="font-family: Arial,Helvetica,sans-serif;"> Vav = 8 m/s is the runner's average speed <span style="font-family: Arial,Helvetica,sans-serif;"> 3. Instantaneous speed is the speed travelled in a certain moment. Average speed is the distance traveled divided by the time taken to travel that distance. <span style="font-family: Arial,Helvetica,sans-serif;"> 4. A = (Delta) speed / Time interval <span style="font-family: Arial,Helvetica,sans-serif;"> A = 100 / 10 <span style="font-family: Arial,Helvetica,sans-serif;"> A = 10 m/s is the vehicle's average acceleration

<span style="font-family: Arial,Helvetica,sans-serif;">6. a) <span style="font-family: Arial,Helvetica,sans-serif; text-decoration: line-through;"> -25/36 <span style="font-family: Arial,Helvetica,sans-serif;"> 1.4 m/s <span style="font-family: Arial,Helvetica,sans-serif;">b) negative <span style="font-family: Arial,Helvetica,sans-serif;">7. a) constant <span style="font-family: Arial,Helvetica,sans-serif;">b) accelerating <span style="font-family: Arial,Helvetica,sans-serif;">c) slow fast slow <span style="font-family: Arial,Helvetica,sans-serif;">d) fast slow fast <span style="font-family: Arial,Helvetica,sans-serif;">8. <span style="font-family: Arial,Helvetica,sans-serif; text-decoration: line-through;">??? <span style="font-family: Arial,Helvetica,sans-serif;">50mi/h <span style="font-family: Arial,Helvetica,sans-serif;">9. No because you go at different speeds to different places but the average of all the speeds is 15 m/s <span style="font-family: Arial,Helvetica,sans-serif;">10. **.. . . . . . . …** <span style="font-family: Arial,Helvetica,sans-serif;">11. 20m/s <span style="font-family: Arial,Helvetica,sans-serif;">In one hour you go 100 miles. In one second you go 45 meters
 * <span style="font-family: Arial,Helvetica,sans-serif;">Physics to Go **
 * <span style="font-family: Arial,Helvetica,sans-serif;">What do you think now? **

<span style="font-family: Arial,Helvetica,sans-serif;">Physics Plus <span style="font-family: Arial,Helvetica,sans-serif;"> Rebounding – bouncing off a surface and changing direction <span style="font-family: Arial,Helvetica,sans-serif;">Assume acceleration is constant during entire process <span style="font-family: Arial,Helvetica,sans-serif;">Example: Bouncing ball <span style="font-family: Arial,Helvetica,sans-serif;">1.Dropping to floor <span style="font-family: Arial,Helvetica,sans-serif;">2.Compresses until stopping <span style="font-family: Arial,Helvetica,sans-serif;">3.Bouncing back up <span style="font-family: Arial,Helvetica,sans-serif;">1. 100 <span style="font-family: Arial,Helvetica,sans-serif;">2. 5 <span style="font-family: Arial,Helvetica,sans-serif;">3. a) 5m/s <span style="font-family: Arial,Helvetica,sans-serif;">b) 5 m/s <span style="font-family: Arial,Helvetica,sans-serif;">c) 5 m/s <span style="font-family: Arial,Helvetica,sans-serif;">

<span style="font-family: Arial,Helvetica,sans-serif;">Section 3
<span style="font-family: Arial,Helvetica,sans-serif;">A girl pushing a ball while walking, then she starts to jog while continuing pushing the ball, then she runs with the ball and her hat falls off. There is a dog driving in a car and seems to be going fast.
 * <span style="font-family: Arial,Helvetica,sans-serif;">What do you see? **

<span style="font-family: Arial,Helvetica,sans-serif;"> A force is the push behind the ball that allows the ball to move fast. A force behind a tennis ball does not have to be as strong because the ball is lighter and has less weight. The force given to a bowling ball has to be greater because the ball is heavier.
 * <span style="font-family: Arial,Helvetica,sans-serif;"> What do you think? **

<span style="font-family: Arial,Helvetica,sans-serif;">An equation for Newton's First Law of Motion. Acceleration = force / mass. A = F / m. F = m x a. a = F / m. m = F / a. 1 N = 1kg x m/s^2. Force of a ruler, a spring, a rubber band, a magnet, a hand and a bat hitting a ball. Newton's second law: acceleration is caused by unbalanced forces. If you push a small cart with the largest force you can, the cart will move a very far distance. If you push a car with that same force, acceleration will be much smaller. Calculating Newton's Second Law of Motion. F = mt x a <span style="font-family: Arial,Helvetica,sans-serif;"> 1) Newton's second law of motion is acceleration equal to force divided by mass. <span style="font-family: Arial,Helvetica,sans-serif;"> 2) If the mass is greater, the force will be less. If the mass is less than the force will be great and the object will move fairly far. <span style="font-family: Arial,Helvetica,sans-serif;"> 3) The object's force is 30 N. Its mass and its acceleration has to equal 30. <span style="font-family: Arial,Helvetica,sans-serif;"> 4) My weight would stay the same but my mass would decrease
 * <span style="font-family: Arial,Helvetica,sans-serif;"> Physics Talk **
 * <span style="font-family: Arial,Helvetica,sans-serif;"> Checking Up **

<span style="font-family: Arial,Helvetica,sans-serif;">Physics To Go <span style="font-family: Arial,Helvetica,sans-serif;"> 1. <span style="font-family: Arial,Helvetica,sans-serif;">3. a = F / m <span style="font-family: Arial,Helvetica,sans-serif;"> a = 42 N / .30 kg <span style="font-family: Arial,Helvetica,sans-serif;"> a = 140 m/s2 <span style="font-family: Arial,Helvetica,sans-serif;"> 4. F = m x a <span style="font-family: Arial,Helvetica,sans-serif;"> F = .040 kg (20.0 m/s2) <span style="font-family: Arial,Helvetica,sans-serif;"> F = .8 N <span style="font-family: Arial,Helvetica,sans-serif;"> 5. a) An object will stay in motion until it is stopped. If a bowling ball was given enough force and is coming toward you, stopping it is going to be very difficult because of its mass. The bowling ball won't travel as far because of its weight. The baseball will be easier and go farther because it is lighter then a bowling ball. <span style="font-family: Arial,Helvetica,sans-serif;"> b)The acceleration of the bowling ball will be less than the acceleration of the baseball. <span style="font-family: Arial,Helvetica,sans-serif;"> 9. Yes it is because that was the force that is causing the ball to accelerate. It is the way that the ball started moving. It will stop when the object is stopped. <span style="font-family: Arial,Helvetica,sans-serif;"> 10. 50 N + 40 N = 90 N <span style="font-family: Arial,Helvetica,sans-serif;"> 11. <span style="font-family: Arial,Helvetica,sans-serif;"> 12. a = f / m <span style="font-family: Arial,Helvetica,sans-serif;"> a = 125 N / 700 g <span style="font-family: Arial,Helvetica,sans-serif;"> a = .18 m/s^2 <span style="font-family: Arial,Helvetica,sans-serif;"> 15. F = m x a <span style="font-family: Arial,Helvetica,sans-serif;"> F = (12.8 kg) (9.8 m/s^2) <span style="font-family: Arial,Helvetica,sans-serif;"> F = 125.44 N <span style="font-family: Arial,Helvetica,sans-serif;"> 18. Acceleration and force both depend on the weight of an object. The more force you put into an object with a small mass, the acceleration will be very large. Putting in the same about of force on a larger object, the acceleration will be a lot slower.

<span style="font-family: Arial,Helvetica,sans-serif;"> Force is a push or pull on an object that causes acceleration to occur. If you put a lot of force into a tennis ball then the acceleration will be very great. If you put the same amount of force into a bowling ball, then the object will have less of an acceleration because the mass is so great.
 * <span style="font-family: Arial,Helvetica,sans-serif;"> What do you think now? **

<span style="font-family: Arial,Helvetica,sans-serif;">Section 4
<span style="font-family: Arial,Helvetica,sans-serif;">Falling apples, red and green. A girl throwing the green apple and just dropping the red one. A boy is timing how long it takes it reach the ground. There is a cat and a dog also. <span style="font-family: Arial,Helvetica,sans-serif;">The amount of force you put behind the object when you are throwing it. Also how far you throw it. <span style="font-family: Arial,Helvetica,sans-serif;">b) Yes <span style="font-family: Arial,Helvetica,sans-serif;">c) <span style="font-family: Arial,Helvetica,sans-serif;">4. a) They don’t change <span style="font-family: Arial,Helvetica,sans-serif;">5. a) The ball will stay back when they move forward <span style="font-family: Arial,Helvetica,sans-serif;">6. a) Vertical components of velocity increase on the way down. The horizontal components are unchanged. Velocity increases on the way up. <span style="font-family: Arial,Helvetica,sans-serif;"> b) If you stay at a constant speed the ball will come back to you but if you increase your speed the ball will not be where you want it
 * <span style="font-family: Arial,Helvetica,sans-serif;">What do you see? **
 * <span style="font-family: Arial,Helvetica,sans-serif;">What do you think? **
 * <span style="font-family: Arial,Helvetica,sans-serif;">Investigate **
 * 1) <span style="font-family: Arial,Helvetica,sans-serif;">a) Reach the floor at the same time.
 * 2) <span style="font-family: Arial,Helvetica,sans-serif;">a) They reach the floor at the same time still
 * 3) <span style="font-family: Arial,Helvetica,sans-serif;">a) No

<span style="font-family: Arial,Helvetica,sans-serif;">

<span style="font-family: Arial,Helvetica,sans-serif;">Projectile motions are crucial to your voice overdub of sporting events. Projectile's only force is weight. Launched through the air. Ignore air resistance. Trajectory is the path of projectile. Ground to ground launches are symmetrical around the highest point (y-max). X and Y information are independent from each other. Ay = -9.8 m/s^2 and the Ax = 0 always. Free fall's only force is weight but 1 dimensional motion (only vertical). Vertical positions of free fall to projectile are same
 * <span style="font-family: Arial,Helvetica,sans-serif;">Physics Talk **

1. Yes, they will both hit at the same time because they have the same acceleration. 2. It's velocity does not remain the same, it accelerates. 3. The ball's velocity at its highest point is 0 and its acceleration is -9.8m/s^2.
 * Checking Up**

1. O - - - - - O O - - - - - - - - O O - - - - - - - - - - - O O - - - - - - - - - - - - - - O 2.O - - - - - - - - - O O - - - - - - - - - - - - - - - - - - - - - O O - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - O O - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - O 4. Everybody thought that the one that was dropped would hit the ground faster than the one that went horizontally because the horizontal angle it was shot at would make the bullet stay in the air longer because it is not going straight down, it is going horizontally while falling. 6. Horizontal motion has no effect on vertical motion, and vice versa. If you go 10mph right while moving 5mph up and then change to 15mph right, your vertical motion will not change. You will still be moving 5mph up even though your horizontal speed changed. If you changed your vertical speed, your horizontal will not change. For example if you are going 10mph right and up and change to 15mph up, you will still be moving 10mph right. 7. Arrow A will hit the ground quicker the arrow B even though they both were dropped at the same time from the same height. Arrow B is not going directly down so it will take longer for it to reach the ground. Arrow A's path to the ground is also shorter than arrow B's path to the ground. 8. 2^2 + 3^2 = r^2 3.6 = r tan^-1 (2/3) = 33.7 degrees 9a. velocity = 15 cos 37 = 11.98m/s 9b. 11.98 x 2 = 23.96m 10a. 12 cos 45 = 8.5m/s 10b. 8.5/2 = 4.2m 11. The pitcher pitches the ball at a velocity of 90 miles per hour. The batter takes a big swing and hits the ball with a force of 300N. The ball was hit with enough force to make it travel travel into the outfield. While the fielder accelerates to retrieve the ball that went by him, the batter sprints into second base and slides, ending with a double. The hard and long hit ball gives enough time for a runner, who started at second base, to score, giving the batter a run batted in, or an RBI. The fielder throws the ball back to the pitcher for the next at bat.
 * Physics to Go**

Some factors that affect how far an object thrown into the air travels before landing are the initial height and velocity of the object being thrown. If the object starts at a higher initial height, it will take longer for the object to come back and hit the ground. If the object's velocity is faster, then the object will travel higher into the sky, meaning that it will take longer for the object to come back to the ground.
 * What Do You Think Now**

Section 5
**What do you think?** Being launched from the ground at different angles changes where the object lands. A greater launch speed causes an object to move faster **Physics Talk** Modeling Projectile Motion Motion. Constant speed along a straight line. Corresponds to the amount of launch speed and its direction. Downward acceleration at 9.8 m/s^2. caused by the Earth's gravitational force. takes effect immediately upon launch Models Mathematical model- the table of times, speeds, and distances during falling. Physical model- the evenly spaced strings calculated lengths. All balls travel in parabolas. The 45 degree launch produces the greatest rage. Distance traveled at pairs of aneles (30 and 60, 20 and 70, 10 and 80...) are identical. Complementary angles of a ground to ground launch have the same ranges not the same TIME, same distance (horizontal). Small angles have greater horizontal velocity but are in the air a short time. Large angles have smaller horizontal velocities but are in the air a long time **Checking up** 1. Two types of motion that help you understand the trajectory of a projectile are constant speed and downward acceleration. 2. The fundamental requirement a scientist must meet when proposing a model of some natural phenomenon is that the model must match reality in nature. 3. Small angles have greater horizontal velocity but are in the air a short time while large angles have smaller horizontal velocities but are in the air a long time. 1. 45 Degree angles produce the greatest range because they travel the furthest. 2. a) If the launch angle is greater then 45 degrees, it is more __b) If it is greater then 45 degrees,__ it is less 3. a) 60 b) 75 4. They aren't trying to get the farthest range, they divers want to hit the water at a smaller angle 5. He knew how to time his jump to provide him with a 45 degree jump, giving him a wide range 6. a) It has none b) to the left 7. 29.4 m/s 5 m/s 15 m 8. 30 or 60 degrees 9. The one with the angle closest angle to 90 degrees 10. a) down b) 4.5 s c) 90 m
 * Physics To Go**

The angle of the trajectory determines the distance the object travels; at 45 degrees, the object has the longest range.
 * What Do you think now?**

Section 6
You need to bend your knees slightly and push off your feet as hard as you can to jump. There needs to be enough force to push the mass of yourself off the ground. The force in the ground is equal to the force that you are exerting on it. The boy in the picture is pushing really hard off the wall so he will go very fast and very far.
 * What do you think?**

Newton's third law of motion states that forces come in pairs; the force of object A on object B is equal in strength and opposite in direction to the force of object B on object A. A free body diagram is a diagram showing the forces acting on an object. They can be used to show the different forces. A center of mass is the point at which all the mass of an object is considered to be concentrated.
 * Physics Talk**

1. Newton's third law of motion states that if one object acts on another, the same amount of force is transfered between the two objects. 2. Since earth pulls down a certain mass with the force of gravity, gravity is also acting upon the earth, pushing objects that are pushing up, down. 3. A free body diagram illustrates the different forces acting upon an object
 * Checking Up**

1. Yes, equal but opposite 2. The chairs do not have any intelligence, but they have the same effect as the ground. If you push on the ground, the ground will return a force equal to yours and opposite to your weight. When you push on the chair, the force you create will go through the chair and into the ground. Then, the ground will return a force equal to yours and opposite to your weight. The force that the ground creates will go through the chair again and then back to you. Overall, there is a deflection involved. No but "restoring" forces balance downward weight. 3. The scale measures how much force you are exerting on it. The scale acts as if it was the ground, except the scale actually measures your force. If you are heavy, you will put more force on the scale, so the scale will show a larger number as your weight. Spring with needle attached, calibrated. 4. Equal but opposite break because Fball is too big for material to withstand 5. When a big linebacker tackles a small running back, the running back will feel the force of the linebacker. Since the linebacker is heavier, he will exert more force on the running back than the running back will on the linebacker. Since the linebacker is heavier, he will knock down the small running back. equal but opposite The smaller player has bigger accel. 6. Equal 7. Padding causes lower acceleration which reduces force on hand. 8a. In physics, if you put force on the ground, the ground will return the same amount of force back at you. I can make this more exciting by putting it in a conversation in a sportscast during my sports movie project. 8b. The ground produces a force when something is forced to the ground. If something puts force on the ground, the ground will return the same exact amount of force that put force on the ground.
 * Physics To Go**

<span style="font-family: Arial,Helvetica,sans-serif;">When you jump, your force should be to the ground. The ground will return the same amount of force back at you. The more force you put on the ground, the higher you will jump.
 * <span style="font-family: Arial,Helvetica,sans-serif;">What Do You Think Now **

<span style="font-family: Arial,Helvetica,sans-serif;">Section 7
Some sports require special shoes because they are played on different surfaces. You use cleats in soccer to run faster and not slip. Cleats in baseball because it is hard to move with flat shoes on clay. Hockey you have wear use skates. Basketball you have shoes with a string grip because the wood floors are slippery
 * What do you think**

<span style="font-family: Arial,Helvetica,sans-serif;">You can measure force with a spring scale. The shoe did not accelerate horizontally was because of friction between the shoe and the surface. The force applied was equal to the frictional force. Pulling and frictional forces are equal in strength and the shoe did not move vertically. The perpendicular force to the surface is the normal force. The normal force is in the opposite direction of the shoe's weight <span style="font-family: Arial,Helvetica,sans-serif;">The coefficient of sliding friction is equal to the force of friction divided by normal force (Ff / Fn). The coefficient of sliding friction does not have any units, is usually in decimal form, and is valid only for the pair of surfaces in contact when the value is measured; any change in surface may cause the coefficient of sliding friction to change
 * <span style="font-family: Arial,Helvetica,sans-serif;">Physics Talk **

<span style="font-family: Arial,Helvetica,sans-serif;">1. Their net force is zero because they are equal and the forces go in opposite directions. <span style="font-family: Arial,Helvetica,sans-serif;"> 2. It has no units because both dividends are measured in N <span style="font-family: Arial,Helvetica,sans-serif;"> 3. To find the coefficient of sliding friction is the equation is force of friction divided by normal force
 * <span style="font-family: Arial,Helvetica,sans-serif;">Checking Up #1-3 **

<span style="font-family: Arial,Helvetica,sans-serif;">Physics Plus <span style="font-family: Arial,Helvetica,sans-serif;">a) <span style="font-family: Arial,Helvetica,sans-serif;">

1. Softball, when the field is normal the clay is the ball doesn’t bounce too much or too little and the grass is easy to run on and the ball rolls on the grass normally. If it is too went the ball doesn’t bounce at all and it is harder to run the ball rolls a lot on the grass and it is hard to run without slipping. If it is too dry the ball bouncing a lot and it is easier to run, on the grass the ball slows down and it is easy to run. When running on a wet field you can take lighter steps so you don’t sink into the clay/dirt as much.
 * Physics To Go**

2. In snowboarding people wax and sharpen their boards to insure the least amount of friction on the snow.

3. No and she needs to be aware of how more or less slippery the floor is compared to the home court

4. I don’t know if they have different shoes but hey should. Each surface is very different. The grass and clay give more the floor and are less slippery.

5.

6.a) 9800 b) 5390 N c)

7. The forces of air and water resistance do change when speeds change. For example, it is much easier to stop water's motion when it is coming out of a sink than it is to stop water coming out of a fire truck hose.

8. When there is a maximum frictional force, there definitely is a limit on how fast you can start. If there is a maximum, then you cannot go above the maximum. Buying shoes with a much smoother sole will solve this problem.

10. Friction is important in running because friction allows you to push off of the ground and accelerate. Without friction you cannot accelerate. Cleats are used for extra friction. Therefore, cleats allow you to accelerate much faster.

11. The runners are lining up at the starting line for the race. The runners a getting into a good starting position. To accelerate, the runners will use the friction between themselves and the ground. The runners have spikes on the bottom of their shoes for extra friction, which means they will have the ability to accelerate faster. And they are off, and accelerating very fast.

Some sports require different shoes because different sports are played on different surfaces and too be able to play most sports you need shoes that give you i decent amount of friction. Different shoes are useful for different sports because you need friction to go fast and run without falling. In the snow sports you need the least amount of friction possible to go faster, same for those with wheels like rollerblading
 * What Do You Think Now?**

(I forgot to write down the percent error equation)
 * Lab**
 * Mass (g) || Mass (kg) || Measured Time (s) || Measured Distance (m) || Ff (N) || Acceleration (m/s^2) || Calculated vi (m/s) || Calculated Time (s) || % error ||
 * 240 || .24 || 1.59 || 7.13 || .78 || 3.25 || 1.90 || 3.21 ||  ||
 * 240 || .24 || 1.68 || 7.38 || .78 || 3.25 || 1.66 || 3.51 ||  ||
 * 240 || .24 || 1.87 || 9.02 || .78 || 3.25 || 1.77 || 4.45 ||  ||

Section 8
1. The change in height effects the size of the pole the person can use to get over the fence 2.The weight of the person, the speed at which you run, the force of the push on the ground.
 * What Do You Think**

//Prelab Activity:// Hold one end of a ruler on the table and press down on the other end. Try to get a penny to travel close to the height of the ceiling without hitting the ceiling. a. Record your technique for blasting the penny high in the air. Bending the ruler as far as it can horizontally go without breaking. Tilting the ruler upward while bending. b. What factors about the ruler and how it is positioned determine the height the penny achieved? Deflection of ruler (force, elasticity), length of ruler, placement of penny, mass of object. //Instructions:// 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? How the placement of the penny affects the height of the penny. b. What data will you record? Where you place the penny and how high it goes c. What tools will you use to make your measurements? A penny, a ruler, and a yard stick d. How will you analyze your data? We look at what we collected to try to find a pattern that is relative between the placement of the penny and how high it went. When a force acts on a object, the speed and position of the object may change. Energy comes in various forms. Two very important forms of energy are kinetic energy (energy associated with motion_ an gravitational potential energy (energy associated with position). When forces act on objects, energy changes from one form to another, but the sum of the kinetic and potential energy (the total energy) remains constant. The concept that the total energy remains constant is referred to as the law of conservation of energy. While a ball is rising or falling, the sum of the gravitational potential energy and the kinetic energy remain constant. Whenever a force applied to an object over a distance (in the same direction or opposite direction of the force), work is done. Work is a precisely defined physics quantity that equals the force multiplied by the distance. The coin in the investigation is a good example of work conservation of energy. Force was applied to the ruler to bend it a certain distance. This was the work done on the ruler to add energy. After that, the ruler had elastic potential energy.
 * Investigate**
 * Placement || Height Trial 1 || Height Trial 2 ||
 * Top of the ruler || 90 cm || 95 cm ||
 * One fourth down the ruler || 45 cm || 55 cm ||
 * Middle of ruler || 20 cm || 15 cm ||
 * Physics Talk**

Work Calculation: W = F * d Elastic (spring) potential energy Calculation EPE = 1/2kx^2 K = the spring constant in newtons per meter (N/m) X = the amount of bending in meters (m)

Gravitational potential energy Calculation: GPE = mgh

Kinetic Energy Calculation: KE = 1/2 mv^2 The unit of work or energy is called the joule (J) 1J = 1N*m 1J = 1kg * m^2/s^2 J = 1N*m = 1 (kg*m^2/s^2)

1. What is required for the energy of an object to change? Force 2. From where does the penny that is launched into the air get its energy? The ruler 3. From where does the pole vaulter get energy needed to bend the pole and then rise over the bar? Kinetic energy from running 4. What are the units for work, kinetic energy, gravitational potential energy and spring potential energy? Joules
 * Checking Up**

1. Describe the energy transformations in the shot put. The person puts energy into throwing the shot put and the shot put takes that energy and uses it to project and then lands on the ground ( Win + KE + GPE = KE Wout) 2. Describe the energy transformation in golf. The person uses their energy to push the club and the club takes that energy and transfers it to the ball and the balls rolls (EPE + KE + Win = KE + GPE + Wout) 3. 7.35 m 4. Because you need to factor in all of the energy that is putting into the ground (initial velocity) 5. The more the poles bend the more energy is created and the more energy the more heat is created. (heat leaves the potential energy is less ) 6. ??? (9.6) 7. ??? ( He went higher, 11) 8. a) 44 b) No. That it is in free fall 9. a) b)  10. a) b) 11. 12. a)
 * Physics To Go**

b)

c) d) 13. GPE + EPE + KE = KE + Wout 14. Win = KE + GPE 15. The pitcher throws the ball towards the player, the ball has kinetic energy. The ball has kinetic energy when it is hit in the air. Once it reaches its highest point, the ball has gravitational potential energy with a velocity of zero. As it falls back down to the earth there is kinetic energy and after hitting the ground, the ground does work. 16. The soccer ball rolls towards the player it has kinetic energy as it is moving towards him. The player runs in the direction of the ball and uses energy in order to do work. The ball now has gravitational potential energy as it is rising up after being kicked. Then the balls hits the ground in the goal.

The pole-vaulter can't reach 12 m height work that is done on the pole. The GPE is the gravitational potential energy and stands for the object/person being above ground has to be equal with the work done because of the law of conservation of energy. The amount of energy has to stay the same. If the mass is increased, then the work done will have to be increased as well because of the initial velocity
 * What Do You Think Now?**

Section 9
<span style="font-family: Arial,Helvetica,sans-serif;"> Figure skater has jumped in the air, spinning, and the helicopter is timing the hang time.
 * <span style="font-family: Arial,Helvetica,sans-serif;">What Do You See? **

<span style="font-family: Arial,Helvetica,sans-serif;"> No, it isn't possible for some athletes to defy the pull of gravity. It is a set pull, and will not change for certain people. No matter who it is, gravity is the same, even if one athlete is better than the other. A world class figure skater does not defy gravity to remain in the air long enough. They are skilled to get a good initial velocity to spring into the air for as long as possible.
 * <span style="font-family: Arial,Helvetica,sans-serif;"> What Do You Think? **

<span style="font-family: Arial,Helvetica,sans-serif;"> 1. a) 20 <span style="font-family: Arial,Helvetica,sans-serif;"> b) 2/3 s <span style="font-family: Arial,Helvetica,sans-serif;"> c) No <span style="font-family: Arial,Helvetica,sans-serif;">2. a) 1s <span style="font-family: Arial,Helvetica,sans-serif;"> b) No <span style="font-family: Arial,Helvetica,sans-serif;">4. a) .70m <span style="font-family: Arial,Helvetica,sans-serif;">5. a) .90m b) .20m 6. a) 1.2m b) .5m 7. a) b) EPE = 483.5 J <span style="font-family: Arial,Helvetica,sans-serif;"> Peak position is where there is gravitational potential energy. When you are about to jump and your knees are bent you have elastic potential energy. Although there is no spring, the chemicals in your muscles provide the potential energy. This energy changes to kinetic energy when you are jumping. A person who can jump higher has more gravitational potential energy and a higher peak point. A table can be used to show the amounts of each type of energy. It would show the position and then each type of energy and how many joules you are using for each. The total energy must be conserved. If you are jumping on a trampoline instead of a hard floor, your kinetic energy coming down would change to elastic potential energy because of the springs when you are coming back up. A specific object can lose or gain energy but the whole system must keep equal energy.
 * <span style="font-family: Arial,Helvetica,sans-serif;">Investigate **
 * <span style="font-family: Arial,Helvetica,sans-serif;">Physics Talk **

<span style="font-family: Arial,Helvetica,sans-serif;"> **Checking Up** <span style="font-family: Arial,Helvetica,sans-serif;"> 1) It comes from elastic potential energy when you are bending your knees. The energy comes from chemicals in your muscles. <span style="font-family: Arial,Helvetica,sans-serif;"> 2) In the launch position and at the peak of your jump, the person will have gravitational potential energy. As they are jumping up though there will be kinetic energy, then it turns into gravitational potential energy. <span style="font-family: Arial,Helvetica,sans-serif;"> 3) Nuclear energy, sound energy, and light energy are all different types. They are energies due to heat.

<span style="font-family: Arial,Helvetica,sans-serif;">1. <span style="font-family: Arial,Helvetica,sans-serif;">2. W GPE KE W <span style="font-family: Arial,Helvetica,sans-serif;">3. Frame by Frame, Data Studio <span style="font-family: Arial,Helvetica,sans-serif;">4. They should be required to provide observable evidence. The other person because there is already all of the proof to support that you can’t defy gravity on earth <span style="font-family: Arial,Helvetica,sans-serif;">5. More force and loose weight <span style="font-family: Arial,Helvetica,sans-serif;">6. <span style="font-family: Arial,Helvetica,sans-serif;">a) 1J <span style="font-family: Arial,Helvetica,sans-serif;">b) 10J <span style="font-family: Arial,Helvetica,sans-serif;">c) 10J <span style="font-family: Arial,Helvetica,sans-serif;">d) 10J <span style="font-family: Arial,Helvetica,sans-serif;">e) 10J <span style="font-family: Arial,Helvetica,sans-serif;">7. <span style="font-family: Arial,Helvetica,sans-serif;">a) 1J <span style="font-family: Arial,Helvetica,sans-serif;">b) 10J <span style="font-family: Arial,Helvetica,sans-serif;">c) 10J <span style="font-family: Arial,Helvetica,sans-serif;">d) 10J <span style="font-family: Arial,Helvetica,sans-serif; margin-left: 0in; text-indent: 0in;">e) 10J
 * <span style="font-family: Arial,Helvetica,sans-serif;">Physics to go **

<span style="font-family: Arial,Helvetica,sans-serif;">8. <span style="font-family: Arial,Helvetica,sans-serif;">a) 1J <span style="font-family: Arial,Helvetica,sans-serif;">b) 10J <span style="font-family: Arial,Helvetica,sans-serif;">c) 10J <span style="font-family: Arial,Helvetica,sans-serif;">d) 10J <span style="font-family: Arial,Helvetica,sans-serif;">e) 10J <span style="font-family: Arial,Helvetica,sans-serif;">9. <span style="font-family: Arial,Helvetica,sans-serif;">10.  <span style="font-family: Arial,Helvetica,sans-serif;">11.a) <span style="font-family: Arial,Helvetica,sans-serif;">b) <span style="font-family: Arial,Helvetica,sans-serif;">12. a) <span style="font-family: Arial,Helvetica,sans-serif;">b)  <span style="font-family: Arial,Helvetica,sans-serif;">13.  <span style="font-family: Arial,Helvetica,sans-serif;">14.  <span style="font-family: Arial,Helvetica,sans-serif;">15.

<span style="font-family: Arial,Helvetica,sans-serif;">16. 17.
 * KE || GPE || EPE || Total ||
 * 100 || 0 || 0 || 100 ||
 * 0 || 0 || 100 || 100 ||
 * 0 || 100 || 0 || 100 ||
 * 100 || 0 || 0 || 100 ||
 * 0 || 0 || 100 || 100 ||
 * ||  ||   || Total ||
 * 0 || 1000 || 0 || 1000 ||
 * 800 || 200 || 0 || 1000 ||
 * 0 || 0 || 1000 || 1000 ||
 * KE || GPE || EPE || Total ||
 * 0 || 1000 || 0 || 1000 ||
 * 500 || 500 || 0 || 1000 ||
 * 1000 || 0 || 0 || 1000 ||

1. 2. 3.
 * Physics Plus**

<span style="color: #000000; font-family: Arial,Helvetica,sans-serif;">Hang time does not exist, and therefore, it does not defy gravity for some people. Gravity (9.8) is a constant number on earth, and is the same for everybody, even if you are a premier athlete. This can be showed in various frames of a slow motion video for example, by marking off the feet, showing the displacement (changes in distance) of the feet. A world-class figure skater cannot defy gravity either. She may jump higher than other times, but she can not remain in the air for hang time. If the maximum height were to change, it would not be by very much.
 * What Do You Think Now?**