If radius of a spherical bubble starts to increase with time t as `r=0.5t`. What is the rate of change of volume of the bubble with time `t=4s`?

The radius of a spherical soap bubble is increasing at the rate of 0.3cm/s. Find the rate of change of its: Volume when the radius is 8 cm.

The radius of a spherical soap bubble is increasing at the rate of 0.5 cm per second. Find the rate of change of its volume, when the radius is 10 cm.

The radius of an air bubble in increasing at the rate of 0.5cm/s. Find the rate of change of its volume, when the radius is 1.5 cm.

The radius of a spherical soap bubble is increasing at the rate of 0.2 cm/sec. Find the rate of increase of its volume when the radius is 4 cm.