WORK AND MECHANICAL ADVANTAGE PROBLEMS (pages 98 …



WORK AND MECHANICAL ADVANTAGE PROBLEMS (pages 98 – 114)

Show your work for all problems where math equations are required or no credit!!

1. Write the formula for work: N x m = J

2. You move a box 100 meters with 5 N of force. How much work did you do?

5N x 100 m = 500 J

3. A box with a mass of 10 kg being pulled by the force of gravity at 10 m/sec2 is lifted

upward 10 meters. How much work is done? 10 kg x 10 m/ sec2 x 10 m = 1000 J

4. Write the formula for mechanical advantage. MA = output force / input force

5. Draw an incline plane. Label the input and output force. Write the formula for the

ideal mechanical advantage for a incline plane

input force →[pic] ↑ output force

6. Draw a lever (1st class). Label the input and output force. Write the formula for the

ideal mechanical advantage of a lever.

Input force ↓ [pic]↑ output force

Length of input force lever / length of output force lever = MA

7. An incline plane has length of 9 meters and a height of 3 meters. What is its M. A.? MA = 9/3 = 3

8. A lever has a distance from the fulcrum to the input force of 10 meters and a distance

from the fulcrum to the output force of 2 meters. What is its M. A.? MA = 10/2 = 5

9. Write the formula for efficiency. Output work / input work x 100 %

10. If you lift a box 50 m with a force of 100 N what is the output work? If you push the same box 200 m

up a ramp to the same height with a force of 25 N, what is the input work . And what is the efficiency

and mechanical advantage of the ramp? 100 N x 50 M = 5000 J; 25 N x 200 M = 5000 J;

5000 J/ 5000 J x 100% = 100 % efficiency

11. An incline plane requires 500 J of output work and 1000 J of input work. What is the

efficiency of the incline plane? 500J x 1000 J x 100% = 50 % efficiency

12. A lever requires 900 J of output work and 1000 J of input work. What is its

efficiency? 900J / 1000 J =90% efficiency

13. Why are levers more efficient than incline planes? Less friction

14. What is the difference between ideal mechanical advantage and actual mechanical

advantage? Actual mechanical advantage includes the effects of friction

15. You pull a box with 10 N of force up a incline plane and your friend lifts the same

box with 40 N of force. What is the mechanical advantage of the incline plane?

How much farther did you have to move the box than did your friend?

40 N /10 N = 4 = MA; 4 times further

16. You push on a lever with 20 N of force and a box is lifted with 100 N of force. What

is the mechanical advantage of the lever 100 N / 20 N = 5 = MA

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