1) A pitcher claims he can throw a 0.147-kg baseball with as much momentum as a 3.36-g bullet moving with a speed of 1.50 10³ m/s.

(a) What must the baseball's speed be if the pitcher's claim is valid?_________ m/s (b) Which has greater kinetic energy, the ball or the bullet?

Both have the same kinetic energy. The bullet has greater kinetic energy.The ball has greater kinetic energy.

2)A 0.276-kg volleyball approaches a player horizontally with a speed of 15.2 m/s. The player strikes the ball with her fist and causes the ball to move in the opposite direction with a speed of 21.4 m/s.

(a) What impulse is delivered to the ball by the player? (Take the direction of final velocity to be the positive direction. Indicate the direction with the sign of your answer.)__________kg m/s (b) If the player's fist is in contact with the ball for 0.0600 s, find the magnitude of the average force exerted on the player's fist. __________N

3)The force shown in the force vs. time diagram in the figure below acts on a1.4-kgobject.A coordinate plane has a horizontal axis labeledt(s) and a vertical axis labeledF_x(N).A straight line is drawn from (0,2) to (3,2), then from (3,2) to (5,0). A vertical dashed line is drawn from (3,0) to (3,2).

(a) Find the impulse of the force. __________Ns (b) Find the final velocity of the object if it is initially at rest. __________ m/s (c) Find the final velocity of the object if it is initially moving along thex-axiswith a velocity of 1.5m/s. _______ m/s

4) A 45.0-kg girl is standing on a 134-kg plank. The plank, originally at rest, is free to slide on a frozen lake, which is a flat, frictionless surface. The girl begins to walk along the plank at a constant velocity of 1.32 m/s to the right relative to the plank. (Let the direction the girl is moving in be positive. Indicate the direction with the sign of your answer.)

(a) What is her velocity relative to the surface of ice?__________ m/s (b) What is the velocity of the plank relative to the surface of ice? _________ m/s

5)A 70.0-kg person throws a 0.0500-kg snowball forward with a ground speed of 33.5 m/s. A second person, with a mass of 59.5 kg, catches the snowball. Both people are on skates. The first person is initially moving forward with a speed of 3.00 m/s, and the second person is initially at rest. What are the velocities of the two people after the snowball is exchanged? Disregard the friction between the skates and the ice. (Take the direction the snowball is thrown to be the positive direction. Indicate the direction with the sign of your answer.)

thrower	_______ m/s (Give your answer to at least three decimal places.)
catcher	_______ m/s

6) Gayle runs at a speed of 4.45 m/s and dives on a sled, initially at rest on the top of a frictionless snow-covered hill. After she has descended a vertical distance of 5.00 m, her brother, who is initially at rest, hops on her back and together they continue down the hill. What is their speed at the bottom of the hill if the total vertical drop is 15.0 m? Gayle's mass is 45.5 kg, the sled has a mass of 5.15 kg and her brother has a mass of 30.0 kg.________ m/s

7)A 0.034-kg bullet is fired vertically at 208 m/s into a 0.15-kg baseball that is initially at rest. How high does the combined bullet and baseball rise after the collision, assuming the bullet embeds itself in the ball?_______m

8)A1,170-kgcar traveling initially with a speed of25.0 m/sin an easterly direction crashes into the rear end of a9,200-kgtruck moving in the same direction at20.0 m/s(see figure below). The velocity of the car right after the collision is18.0 m/sto the east. Two images depicting a before and after scenario of a car colliding with the back of a truck.

• Before:The car is moving at a velocity of +25.0 m/s. This is shown as a rightward-moving horizontal arrow above the car. The truck is moving at a velocity of +20.0 m/s. This is shown as a rightward-moving horizontal arrow, shorter than that of the car, above the truck.
• After:The car is shown crashing into the back of the truck. At this point, the velocity of the car is shown to be +18.0 m/s. This is shown as a rightward-moving horizontal arrow above the car. The velocity of the truck is shown to bev. This is shown as a rightward-moving horizontal arrow, longer than that of the car, above the truck.

(a) What is the velocity of the truck right after the collision? (Round your answer to at least three decimal places.) ___________m/s (east) (b) How much mechanical energy is lost in the collision? _________J Account for this loss in energy.

9) A 2,000-kg car moving east at 10.0 m/s collides with a 3,000-kg car moving north. The cars stick together and move as a unit after the collision, at an angle of 38.0 north of east and at a speed of 5.08 m/s. Find the speed of the 3,000-kg car before the collision. __________m/s north

10)A billiard ball moving at 5.85 m/s strikes a stationary ball of the same mass. After the collision, the first ball moves at 4.79 m/s, at an angle of 35 with respect to the original line of motion.

(a) Find the velocity (magnitude and direction) of the second ball after collision. (Enter the direction with respect to the original line of motion. Include the sign of your answer. Consider the sign of the first ball's angle.)

________m/s

________

(b) Was the collision inelastic or elastic?