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Question

What is the difference between a simple and a compound machine?

1. A simple machine uses two or more compound machines working together.
2. A compound machine uses two or more simple machines working together.
3. Simple machines only increase force; compound machines only increase distance.
4. Compound machines only increase force; simple machines only increase distance.

For a machine with an efficiency of 80%, what is the work output of the machine if its work input is 2,000 joules?

1. 16 joules
2. 160 joules
3. 1,600 joules
4. 2,500 joules

If a machine requires an effort force of 750 newtons applied over a distance of 2 meters, over what resistance distance is the machine acting if the resistance force has a value of 150 newtons? Assume that it is an ideal machine. (HINT: Use the equation Fe x de = F r x dr)

1. 5 meters
2. 10 meter
3. 150 meters
4. 300 meters

Answer 1

1.) Generally the term compound means that you're combining. The answer is #2.

2.) Multiply the efficiency by the work input: 80% * 2000 = 1600J. (answer #3)

3.) Fe x de = Fr x dr
Effort force = 750 N
Effort distance = 2m
Resistance force = 150 N
So:
750N * 2m = 150N * x m
10m = x (answer #2)