# A car weighing 14,000 N is speeding down the highway at 80 km/h. What is its momentum?

Problem Set Four

1.  .  A car weighing 14,000 N is speeding down the highway at 80 km/h.  What is its momentum?

2.  Two ice skaters stand face to face and “push off” and travel directly away from each other.  The boy has a velocity of 5 m/s and he weighs 750 N.  The girl weighs 480 N.  What is the girl’s velocity?

3.  A 20,000 kg railroad car is traveling at 5 m/s when it collides and couples with a second, identical car at rest.  What is the resulting speed of the combined cars?

4.  A soccer player kicks a 2 kg ball with a force of 900 N.  His toe is in contact with the ball for 2 s.  What is the impulse?

5.  A force of 140 N is required to push a table 5.0 meters across a level floor.  How much work was done?

6.  If 10,000 J of work was done to raise a 225 kg box, how high was the box raised?

7.  What is the velocity of a 1,500 kg car if its kinetic energy is 350 kJ?

8.  A 125 kg mass is on a cliff 55 m high.  What is its potential energy?

9   How much work is done moving a 2.4 kg book to a shelf 4.0 m high?

10.  A 150 pound man runs up a stairway 20 feet above ground level in 15 s.  How much work did the man do?