https://www.youtube.com/watch?v=08BFCZJDn9w

1-An object at rest, or in motion at a constant velocity continues to stay at rest or in motion in a constant velocity unless acted on by a net external force. This is also known as the law of inertia. Which law is this?

a- Newton's 1st law

b-Newton's 2nd law

c-Newton's 3rd law

2-A net external force acting on an object changes its motion (velocity or direction) and the acceleration is in the same direction as the net external force. F = ma. Which law?

a- Newton's 1st law

b-Newton's 2nd law

c-Newton's 3rd law

3-For every action there is a reaction of equal magnitude in the opposite direction. Which law is this?

a- Newton's 1st law

b-Newton's 2nd law

c-Newton's 3rd law

4-Inertia is the measure of an object's...

a-velocity

b-force when it hits you

c-mass

d-weight

https://www.youtube.com/watch?v=qu_P4lbmV_I&feature=emb_title

https://www.youtube.com/watch?v=e1lzB36aHD4

5-Weight and mass are the same thing, true or false?

a-True

b-False

6-Which has a greater momentum, a 120 kg running back running at 8 m/s or a 0.0079 kg bullet traveling at 350 m/s.

a-Running Back

b-Bullet

c-Can't determine

7-There is no loss of energy to deformation, sound, or heat in the collision. What kind of collision is that?

a-Head-on

b-Elastic

c- In-elastic

8-If there is a loss of energy during the collision due to sound, heat, and deformations what type of collision is that?

a-bumper-to-bumper

b-Inelastic

c-Elastic

9-The law in physics that states that the momentum of a "system" before a collision is equal to the momentum of the "system" after a collision is known as

a-Conservation of Charge

b-Conservation of Energy

c-Conservation of Momentum.

10-Which of the following is an example of an inelastic collision?

a-Two football players colliding and their pads make a loud clacking noise, their bodies bend, and there is heat lost due to the friction between their bodies.

b-Two solid pool balls of equal mass strike one other and we can discount the noise made and the friction between the balls and the felt of the pool table.

11-Let's examine over the next few questions an NFL kick as described in the 3rd Law video. The announcer claimed that the ball is struck with "almost a ton of force." First of all, phrases like "almost a ton" drive physics people crazy. Give me a number! So let's guess-timate 1900 lbs of force. Convert that to Newtons. (you can always just Google this one)

12-The kicking video did give a solid number that the duration of the kick was 0.008 seconds. Using the Newtons above the seconds given here, calculate the "Impulse" on the football.

13-The mass of an NFL football is .43 kg. The launch speed of an NFL kick is about 40 m/s. Use the impulse you got in the above answer to calculate the speed of the football, we would predict based on the impulse we calculated. It is much, much higher than the 40 m/s. We have not taken two things into consideration. The first is the loss of energy during the kick on the ball. And we have not accounted for the huge kinetic energy in the leg of the NFL kicker moving through the ball! In other words, this is actually a partially inelastic collision so to get an accurate speed we have to take into accounted mass of the kicker's leg. We will examine this more in Chapter 6! Can't wait!!

The next set of problems deal with a hockey puck striking the padding of a goalie. This is an inelastic collision. The .175 kg hockey puck has an initial velocity of -45 m/s. Notice the negative sign. After it bounces off the .85 kg glove, the puck recoils in the positive direction at 15 m/s.

14-From the information given about the hockey puck, calculate the speed of the recoil of the hockey glove.

15-Calculate the kinetic energy of the glove/puck system BEFORE the collision.

16-Calculate the kinetic energy AFTER the collision. Don't forget the kinetic energy of the glove! :)