Amachine has an efficiency of 70%. how much work does the machine do when 20,000 j of work is done on it?
14,000 j
28,600 j
1,400,000 j
2,860,000 j

The correct answer to the question is A) 14,000 J.

CALCULATION:

As per the question, the efficiency of the engine

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The work done on the machine W = 20,000 J.

Hence, input work W = 20,000 J.

We are asked to calculate the output work.

Let W' is the output work.

The efficiency of a machine is defined as the ratio of output work to input work.

Mathematically efficiency

                                          ⇒ 

                                          ⇒ 

                                                               [ANS]

Hence, the machine will do 14,000 J.