8. how long does it take a 19 kw steam engine to do 6.8 x 107 j of work?

Power is the rate at work is being performed. The time taken by the engine to complete the work is 59. 65 minutes.

Power:

It is defined as the rate of work done or the transfer of energy per unit time. It is measured in the watt.

Where,

P - power

W - work done

- time

Put the values in the formula and solve it for Time,

Therefore , the time taken by the engine to complete the work is 59. 65 minutes.

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3.58 × 10³ seconds or 59.65 minutes

Explanation:

We are given;

We are required to calculate time;

We need to know that;

19 kW = 19,000 Watt

Rearranging the formula;

time = Work done ÷ power

       =  6.8 × 10^7 Joules ÷ 19,000 watt

       = 3578.95 seconds

        = 3.58 × 10³ seconds

But, 60 seconds = 1 minute

Therefore, t = 59.65 minutes