Gravel is being dumped from a conveyor belt at a rate of 40 ft/min, and its coarseness is such that it forms a pile in the shape of a cone whose base diameter and height are always equal. How fast (in ft/min) is the height of the pile increasing when the pile is 5 ft high?
(Round your answer to two decimal places.)




The radius of a sphere is increasing at a rate of 2 mm/s. How fast is the volume increasing (in mm/s) when the diameter is 40 mm? (Round your answer to two decimal places.)