If a snowball melts so that its surface area decreases at a rate of 2 cm2/min, find the rate (in cm/min) at which the diameter decreases when the diameter is 10 cm.

Answer 1

S = surface area = 4πr² = πD², where D is the diameter

dS/dt = 2πD(dD/dt)

-2 = 2π(10)(dD/dt)

So, dD/dt = -1 / (10π)