Physics Exam 2

Two pool balls , each moving at 2 m/s, roll toward each other and collide. Suppose after bouncing apart, each move at 4m/s. This collision violates the conservation of

Energy

A large heavy truck and a small baby carriage roll down a hill ....

none of these

An object lifted 10 meters gains 200 J of potential energy . If the same object is lifted 20 meters the potential energy is

twice as much

Do 100 J of work in 50s and your power output is

2 W

A 4 kg ball has a momentum of 12 m/s. What is the ball's speed ?

3 m/s

Two identical arrows , one with twice the speed of the other , are fired into a hay bale. The faster arrow will penetrate

Four times further than the slower arrow

In both fission and fusion, mass

Is created from energy of other forms

Compared to the mass of a uranium nucleus before splitting , the pieces it splits into have

Less mass

If iron were used as nuclear fuel , it would be best

Neither

The conservation of momentum is most closely related to

Newton's 3rd Law

A rifle recoils while firing a bullet. The speed of the rifle's recoil is small because the

Rifle has more mass than the bullet

When you jump from an elevated position you usually bend your knees ....

about 1/10 as great

U-235 and Pu239 are both

all of these

What task requires the most work ; lifting a 5" kg sack of 2 meters or lifting a 25 kg sack at 4 meters ?

both require the same amount

Uranium 235 ,238,and 239 are different

elements