Question

Select the correct words from the drop-down menus to complete the sentence. The work of a machine can never exceed the work because uses some of the work.

Answer 1

1. Output

2. Input

3. Friction

The work output of a simple machine can never exceed the work input because friction uses some of the work.

Answer 2

Answer: The work OUTPUT of a simple machine can never exceed the work INPUT because FRICTION uses some of the work.

Explanation:

This concept is related to ideal machines and efficiency.

Only ideal machines can convert all the work input into useful work (work ouput).

The efficiency is a concept that tells you the proportion of input work that is transformed into output work.

         Efficiency = (output work / input work) × 100

Ideal machines, those where friction does not exist, have a 100% efficiency, and so ideal machines convert all the input work into useful output work.

Real machines have a efficiency less than 100%. Friction lowers the efficiency and the work outpu is less than the work input, because friction uses work which is converted, mostly, into heat energy or sound energy.