1. How much force is needed to do a 650.0 J of work on a 50.00 kg box that is being pushed to a distance of 8 m? (3 pts)
2. What is the velocity of an 800-g sack falling from a helght of 525.00 meters right before it hits the ground? (5 pts)
3. A man stood right in front of the door of a square room that is 12 m wide. How much work did he do if he pushed against a 500-kg box for 860.0 s to move it to the opposite wall but it did not move? (3 pts)
4. A machine did 2 850 J of work to lift a 1 300.00-kg old car. a) How high was the machine able to move the car? What is the car's potential energy at this height (the height in 'a')? (4 pts)
