Question

A machine starts dumping sand at the rate of 20 m3/min, forming a pile in the shape of a cone. The height of the pile is always twice the length of the base diameter. After 5 minutes, how fast is the area of the base increasing?

Answer 1

When after 5 min the height is 11.516, after 5 min the height is increasing at .7678m/min, after 5 min the base radius is increasing at .19196 m/min, so I already workd out the volume formula v=1/3pir^2h