Why must integration be used to find the work required to pump water out of a tank?
a. different volumes of water are moved different distances.
b. water from the same horizontal planes is lifted different distances.
c. integration is necessary because the acceleration of gravity changes at each level.
d. integration is necessary because w = mgy.

A. Different volumes of water are moved different distances.

Step-by-step explanation:

Integration is used to find work required to pump water out of a tank because different volumes of water are moved different distances and to sum it all we the tool required is integration. Moreover, work done is a path function or an inexact differential. It does depend upon the path followed by the process.

hence the correct answer is A.

c.

step-by-step explanation:

because first you have to add the 4x, 9x, and the 7x together and you get 20x and then you add the last numbers up and you get 5and then you put the subtraction sign in there and that's how you get the answer.

the answer is c: divide the arc's degree measure by 360°, then multiply by the circumference of the circle.