A solid cylindrical ice pillar is melting in the ocean. At time t t\,t hours, the pillar has radius R R\,R metres and height H H\,H metres. The height is maintained such that H=8RH = 8RH=8R throughout the melting process.
The area of the pillar's circular top face, SSS, is decreasing at a constant rate of 1.5 m2 h-1.
Determine the value of dRdt\displaystyle \frac{dR}{dt}dtdR at the instant when R=4R = 4R=4.
Determine the rate of decrease of the volume of the ice pillar at the instant when R=5R = 5R=5.
