Question

When considering the normal power demand as reported by a utility company, the power demand at midnight is 1040 MW. During the first five hours, the power demand rises to 1600 MW, and at the eight-hour mark, the power demand rises to 1960 MW. What is the average rate of change of the power demand with respect to time for the period from 5 hours to 8 hours after midnight? 360 MW 282.5 MW/hour 120 MW/hour 1780 MW/hour None of these

Answer 1

120 MW/hour

Explanation:

The formula of the average rate of change between two points in a function is:

Average rate of change (ARC) = f(x2) -f(x1)/(x2-x1)

Let's think the power demad as a function d(x) depending of the hour of the day, so the variable x= hour of the day.

Now we have:

d(5)= 1600

d(8)= 1960

If we apply the mentioned ARC formula = [d(8)-d(5)] MW/(8-5)hour= (1960-1600)MW/3hour= 360/3=120 MW/Hour