Calculus II

[aussie250]

A cable weighing 0.6 pounds per foot is attached to a small 70-pound robot, and then the robot is lowered into a 40-foot deep well to retrieve a 7 pound wrench. The robot gets out of the well (carrying the wrench) by climbing up the cable with one end of the cable still attached to the robot. How much work does the robot do in climbing to the top of the well?

Thank you!

 

[tkhunny]

How much work is done in the first moment where he moved "dx"?
After moving that far, add a little cable and calculate the next piece of work.