CH. 4 phys 133

The power required to exert 1 N force, over a distance of 1 m in 1 second is

1 W

A 1-kg glider and a 2-kg glider both slide toward each other at 1 m/s on an air track. They collide and stick. The combined mass moves at

1/3 m/s

Which of the following has the largest momentum relative to the Earth?

a pickup truck speeding along a highway

A bow is drawn so that it has 40 J of potential energy. When fired, the arrow will ideally have a kinetic energy that is

40 J.

Marks: 1 A 5000-kg freight car runs into a 10,000-kg freight car at rest. They couple upon collision and move with a speed of 2 m/s. What was the initial speed of the 5000-kg car?

6 m/s

A car moves 4 times as fast as another identical car. Compared to the slower car, the faster car has

16 times the KE.

A 5000-kg freight car moving at 2 m/s runs into a 10,000-kg freight car at rest. They couple upon collision and move away as one body at

2/3 m/s.

What task requires the most work; lifting a 50-kg sack 2 meters or lifting a 25-kg sack 4 meters?

Both require the same amount of work.

if an object has kinetic energy, then it also must have

momentum.

A large metal ball is shot from a cannon with a short barrel. If the same ball were to be shot from cannon with a longer barrel, its muzzle velocity would be

more

A ball is projected into the air with 100 J of kinetic energy which is transformed to gravitational potential energy at the top of its trajectory. When it returns to its original level after encountering air resistance, its kinetic energy is

less than 100 J.

An object may have potential energy because of its

location

When you are in the way of a fast-moving object and can't get out of its way, you will suffer a smaller force of impact if you decrease its momentum over a

long time

In order to catch a ball, a baseball player extends the hand forward before impact with the ball and then lets it ride backward in the direction of the ball's motion .. Doing this reduces the force of impact on the player's hand principally because the

time of impact is increased

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

twice as far as the slower arrow.