Question

Short Answer
In complete sentences, write the answers to the questions on
the lines provided.
1. If two swimmers compete in a race, does the faster swimmer
develop more power?
2. Why is the work output of a machine never equal to the work
input?
3. If a simple machine could be frictionless, how would its IMA and
AMA compare?
4. Compare the effects of a fixed pulley and a movable pulley on the
size and direction of the input force.
5. In a compound machine made up of two simple machines, how is
the work output of the first simple machine related to the work
input of the second simple machine?

Answer 1

1. Yes; because power is the rate of doing work, the swimmer who does the same amount of work in less time produces more power.
2. The work output of a machine is never equal to the work input because some input energy is always lost to friction, sound, heat, or deformation.
3. If a simple machine were frictionless, its ideal mechanical advantage (IMA) would equal its actual mechanical advantage (AMA) because no energy would be lost.
4. A fixed pulley changes only the direction of the input force without reducing its magnitude, while a movable pulley reduces the size of the required input force (provides mechanical advantage) though it may not change the force direction.
5. In a compound machine the work output of the first simple machine becomes the work input of the second simple machine (neglecting any losses between stages).