Practice Problems

Practice Problems
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1. Which requires more work: lifting a 50 kg sack over a vertical distance of 2 meters or lifting a 25 kilogram sack a vertical distance of 4 meters?

2. What is the work on an object that has a 20 kg force pushing it over a distance of 2 meters?

3. What is the efficiency of a pulley system when its work out equals 100 joules and its work in equals 150 joules?

4. What is the Potential Energy of an object that has a mass of 40 kg at a height of 17 meters?

5. What is the Kinetic Energy of a 102 kg object moving at a speed of 30 m/s?

6. You and your brother are throwing a ball in an airplane. Does the Kinetic Energy of the ball depend on the speed of the plane?

7. A car is pushing on the road with a force of 500 Newtons. How much is the road pushing back on the car?

8. A person's weight is the result of gravitational force of the earth on one's body. What is the corresponding reaction force?

9.What is the Mechanical Advantage of a machine if the effort force is 20 Newtons and the resistance force is 5 Newtons.

10. What is the Ideal Mechanical Advantage of a Wheel and Axle if the radius of the wheel is 6 cm and the radius of the axle is 3 cm?

This Page was last edited on Thursday, July 27, 2000 .