Question

Based on the law of conservation of energy, how can we reasonably improve a machine’s ability to do work?

A.Move the machine to a different gravitational field.
B.Increase the friction between its moving parts.
C.Reduce the friction between its moving parts.
D.Redefine the machine’s system boundaries.

Answer 1

D. Redefine the machine’s system boundaries.

The Law of Conservation of Energy states that energy can't be created not destroyed. Energy, however, can be changed from one form to another. The law applies to isolated systems only. By redefining and expanding the system (including all factors affecting it) , the machine's ability to do work should improve.

Answer 2

Friction causes energy loss. By conservation of energy, reducing friction will increase work. So ans is C.