1.  Two identical cars have the same speed, one traveling east and one traveling west. Do these cars have the same momentum? Explain.

2.  In Time Square people celebrate on New Year's Eve. Some just stand around but many move about randomly. Consider a system comprised of all of these people. Approximately, what is the total linear momentum of this system at any given instance? Justify your answer.

3. You jump off the top of your house and hope to land on a wooden deck below.  Consider the following possible outcomes

I. You hit but it isn't wood! A camouflaged trampoline slows you down over a time period of 0.2 seconds and sends you flying back up in the air

II. You hit the decked with your knees locked in the straight leg position.  The collision time is 0.01 seconds

III. You hit the deck and bend your legs lengthening the collision time to 0.2 seconds

IV. You hit the deck, but it isn't wood! it simply a piece of paper painted to look like a deck.  Below is an infinite void and you continue to fall, forever.

a)  Which method will involve the greatest force acting on you?

b)  Which method will involve the least amount of force acting on you?

c)  Which method will you land on the deck in the least amount of pain?

d)  Which method will involves the least impulse delivered to you?

e)  Which method involves the greatest impulse delivered to you?

4. A dump truck is being filled with sand. The sand falls straight downward from rest from a height of 2m above the truck bed, and the mass of sand that hits the truck per second is 55 kg/s. The truck is parked on the platform of a weight scale. By how much does the scale reading exceed the weight of the sand and truck?

5. A 46-kg skater is standing still in front of a wall. By pushing against the wall she propels herself backward with a velocity of -1.2m/s. Her hands are in contact with the wall for 0.80s. Ignore friction and wind resistance. Find the magnitude and direction of the average force she exerts on the wall (which has the same magnitude, but opposite direction, as the force that the wall applies to her).

6. On a frictionless horizontal surface, block A (mass 3.00 kg) is moving toward block B ( mass 5.00 kg), which is initially at rest. After the collision block A has a velocity of 1.20 m/s to the left, and block B has velocity 6.50 m/s to the right.

a) What was the speed of block A initially, before the collision?

b) Calculate the change in the total kinetic energy of the system that occurs during the collision.

7. A 28.2 kg cart traveling at 2.24 m/s (this movement defines the positive direction) has a head on perfectly inelastic collision with a 4.7 kg cart traveling at -0.41 m/s. How much kinetic energy is lost in the collision?

8. A 9.7 kg cart traveling at 0.64 m/s (this movement defines the positive direction) has a head on perfectly inelastic collision with a 46.4 kg cart traveling at 1.96 m/s. How much kinetic energy is lost in the collision?

9. What is the momentum of a 94.5 kg woman running with a kinetic energy of 1388 J?