Final Wrap-Up Part II

1. Two blocks of masses 2 and 3 kg are hung from the ends of a lever with negligible mass. At which of the points should the lever be placed on the fulcrum in order to stay in horizontal equilibrium?

• A

• B

• C

• D

A truck moves along a frictionless level road at a constant speed. The truck is open on top. A large load of gravel is suddenly dumped into the truck. The velocity of the truck: Increases. Remains the same. Decreases. Immediately goes to zero.

• Increases

• Remains the same

• Decreases

• Immediately goes to zero

When a ping-pong ball rolling with a speed of 3.0 m/s collides with a bowling ball at rest, the ping-pong's speed after the collision will be close to:

• 0 m/s

• 3 m/s

• 6 m/s

• 12 m/s

Two friends with mass 60 kg and 40 kg skate directly toward each other with speeds 3 m/s and 2 m/s respectively. If they hug each other as they collide, the combined speed of the two friends just after the collision will be

• 2.6 m/s

• 1 m/s

• 2 m/s

• 3 m/s

A tennis ball of mass m rebounds from a vertical wall with the same speed v as it had initially. What is the change in momentum of the ball?

• mv

• 2mv

• 2mvcosθ

• 2mvsinθ

34. Two oscillating systems: spring-mass and simple pendulum undergo SHM with an identical period T. If the mass in each system is doubled which of the following is true about the new period?

• Mass-Spring: T Pendulum: T/√2

• Mass-Spring: T/√2 Pendulum: T

• Mass-Spring: T Pendulum: T

• Mass-Spring: √2T Pendulum: T

A bowling ball moving with speed, v collides head-on with a stationary tennis ball. The collision is elastic, and there is no friction. The bowling ball barely slows down. What is the speed of the tennis ball after the collision?

• nearly v

• nearly 2v

• nearly 3v

• nearly 4v

A 3 kg ball is dropped onto a concrete floor. What is the magnitude of the ball’s change in momentum if its speed just before striking the floor is 7 m/s and its rebound speed is 3 m/s?

• 10 kg-m/s

• 15 kg-m/s

• 30 kg-m/s

• 60 kg-m/s

Two blocks are on a frictionless surface and have the same mass m. Block 2 is initially at rest. Block 1 moves to the left with speed 4v and collides elastically with block 2. What is the final speed of block 1?

• zero

• v

• 2v

• 4v

An object with a mass of 2.0 kg is accelerated from rest. The graph shows the magnitude of the net force as a function of time. At t = 4.0 s the object’s velocity is closest to which of the following?

• 2 m/s

• 4 m/s

• 10 m/s

• 13 m/s