Mechanical Advantage, Work, Power Problems

Name:

1. Classify the following levers.

2. What is the mechanical advantage of an inclined plane that is 4000 centimeters long and 8 meters high?

3. What is the efficiency of a machine that requires 100.0 J of input energy to do 35 J of useful work?

4. A bus steering wheel has a diameter of 50.8 cm. It turns the steering column, which has a diameter of 7.6 cm. If the driver applies 22.3 N of force to turn the wheel how much force does the steering column exert to steer the bus?

5. A mover is loading a 253 kg crate of hammers onto a truck. The upward force on the crate is 2470 N, and 3650 J of work are required to raise the crate from the pavement to the truck bed. a. How far is the crate lifted? Mechanical Advantage, Work, Power Problems b. If the mover does this in 4s, how powerful is he?

6. How efficient is a pulley system if it enables you to lift a 700.0 Newton engine 0.550 meters if you exerted 35.7 Newtons of force while pulling 11.43 meters of rope?

7. A force of 800 Newtons is needed to push a car across a lot. Two students push the car 40 meters. How much work is done?

8. Your car has run out of gas. Fortunately, there is a gas station nearby. You must exert a force of 715 N on the car in order to move it. By the time you reach the station, you have done 27200 J of work How far have you moved the car?

9. How much work is done in lifting a 60Kg crate a vertical distance of 10 meters?

10. A box that weighs 1000 Newtons is lifted a distance of 20 meters in 10 seconds. How many kilowatts of power are produced?

11. You are using 50 N of force to push an empty cart down the hall at school. Your friend, with a mass of 81.6 kg, jumps on the cart and wants to be taken for a ride. You push your friend down the hall for 20 meters before being caught by the Principal. How much work did you do pushing your friend on the cart?

12. A stock boy is told to put boxes of mass 5.0 kg on shelves that are 1.5 meters above the floor. They young man finds that he can do this at a rate of 4.0 per minute. Mechanical Advantage, Work, Power Problems a. How much work will he do in 15 minutes? b. What is his power for this job?

13. Peter used a stick 1.8 meters long to push aside a large rock in the yard. The fulcrum was 0.3 meters from the resistance. What is the mechanical advantage of the stick?

14. A lever is used to lift a heavy load. A 50 N force pushes one end of the lever down 1.2 m and the load rises 0.2 m. Calculate in weight of the load.

15. When moving a 5000 N piano with a pulley system, the workers note that for every 2 m of rope pulled down, the piano rises 0.4 m. a. how much force is required to lift the piano? b. The workers actually pull with 2500 N of force to lift the piano 2m, what is the efficiency of the pulley system?

16. During a major downtown fire, the Leyden Fire Department pumped 400,000 liters of water to the 27th floor of a building 96 meters above the street. How much work was done in the process?