The radius of a sphere is increasing at a rate of 2 mm/s. How fast is the volume increasing when the diameter is 80 mm?

Question

mm^3/s

Answer 1

V = (4/3)*pi*r^3
dV/dt = 4*pi*r^2*(dr/dt)

In this case, dr/dt = 2 mm/s and
r = 80 mm

Do the calculation for dV/dt

Answer 2

12800pi