Reference no: EM13341290

1. A rock is dropped from a high tower and falls freely under the influence of gravity. Which one of the following statements concerning the rock as it falls is true? Neglect the effects of air resistance. 

A) The rock will gain an equal amount of momentum during each second. 

B) The rock will gain an equal amount of kinetic energy during each second. 

C) The rock will gain an equal amount of speed for each meter through which it falls. 

D) The rock will gain an equal amount of momentum for each meter through which it falls. 

E) The amount of momentum the rock gains will be proportional to the amount of potential energy that it loses. 

2. Jennifer is walking at 1.22 m/s. If Jennifer weighs 552 N, what is the magnitude of her momentum? 

A) 97.0 kg ? m/s 

B) 137 kg ? m/s 

C) 68.6 kg ? m/s 

D) 672 kg ? m/s 

E) 951 kg ? m/s 

3. A 0.2-kg steel ball is dropped straight down onto a hard, horizontal floor and bounces straight up. The ball''s speed just before and just after impact with the floor is 10 m/s. Determine the magnitude of the impulse delivered to the floor by the steel ball. 

A) zero N ? s 

B) 2 N ? s 

C) 4 N ? s 

D) 20 N ? s 

E) 200 N ? s 

4. A 0.065-kg tennis ball moving to the right with a speed of 15 m/s is struck by a tennis racket, causing it to move to the left with a speed of 15 m/s. If the ball remains in contact with the racquet for 0.020 s, what is the magnitude of the average force exerted on the ball? 

A) zero newtons 

B) 98 N 

C) 160 N 

D) 240 N 

E) 320 N 

5. A baseball of mass m, initially at rest, is struck by a bat so that it acquires a speed v. If t represents the duration of the collision between the bat and the ball, which one of the following expressions determines the magnitude of the average force exerted on the ball? 

A) (1/2)mv2 

B) mv/t 

C) (1/2)mv2t 

D) mt2/(2v) 

E) mvt

6. An object of mass 3m, initially at rest, explodes breaking into two fragments of mass m and 2m, respectively. Which one of the following statements concerning the fragments after the explosion is true? 

A) They will fly off at right angles. 

B) They will fly off in the same direction. 

C) The smaller fragment will have twice the speed of the larger fragment. 

D) The larger fragment will have twice the speed of the smaller fragment. 

E) The smaller fragment will have four times the speed of the larger fragment. 

7. A bullet of mass m is fired at speed v0 into a wooden block of mass M. The bullet instantaneously comes to rest in the block. The block with the embedded bullet slides along a horizontal surface with a coefficient of kinetic friction ?. 

Which one of the following expressions determines how far the block slides before it comes to rest (the magnitude of displacement s in the figure)? 

A) 

B) 

C) 

D) 

E) 

8. Which one of the following is characteristic of an inelastic collision? 

A) Total mass is not conserved. 

B) Total energy is not conserved. 

C) Linear momentum is not conserved. 

D) Kinetic energy is not conserved. 

E) The change in momentum is less than the total impulse. 

9. Two objects of equal mass collide on a horizontal frictionless surface. Before the collision, object A is at rest while object B has a constant velocity of 12 m/s. After the collision, the two objects are stuck together. What is the speed of the composite body (A + B) after the collision? 

A) 3.0 m/s 

B) 6.0 m/s 

C) 12 m/s 

D) 24 m/s 

E) 36 m/s 

10. A 2-kg stone falls 100 meters near the surface of the earth. It strikes the ground without any rebound thereby making a completely inelastic collision with the earth. Approximately how much kinetic energy is transferred to the earth in this process? 

A) zero joules 

B) 200 J 

C) 2000 J 

D) 10 000 J 

E) 20 000 J 

11. A 3.0-kg cart moving to the right with a speed of 1.0 m/s has a head-on collision with a 5.0-kg cart that is initially moving to the left with a speed of 2.0 m/s. After the collision, the 3.0-kg cart is moving to the left with a speed of 1.0 m/s. What is the final velocity of the 5.0-kg cart? 

A) zero m/s 

B) 0.80 m/s to the right 

C) 0.80 m/s to the left 

D) 2.0 m/s to the right 

E) 2.0 m/s to the left 

12. A 1000-kg car traveling east at 20 m/s collides with a 1500-kg car traveling west at 10 m/s. The cars stick together after the collision. What is the common velocity of the cars after the collision? 

A) 16 m/s, east 

B) 6 m/s, west 

C) 4 m/s, east 

D) 2 m/s, east 

E) 1 m/s, west 

13. A 0.050-kg lump of clay moving horizontally at 12 m/s strikes and sticks to a stationary 0.15-kg cart that can move on a frictionless air track. Determine the speed of the cart and clay after the collision. 

A) zero m/s 

B) 3 m/s 

C) 6 m/s 

D) 9 m/s 

E) 12 m/s 

Problems 14, 15: A stationary 4-kg shell explodes into three pieces. Two of the fragments have a mass of 1 kg each and move along the paths shown with a speed of 10 m/s. The third fragment moves upward as shown. 

14. What is the speed of the third fragment? 

A) zero m/s 

B) 1 m/s 

C) 5 m/s 

D) 10 m/s 

E) 20 m/s 

15. What is the speed of the center of mass of this system after the explosion? 

A) zero m/s 

B) 1 m/s 

C) 3 m/s 

D) 5 m/s 

E) 7 m/s