A circular disc of radius 3 cm is being heated. Due to expansion, its radius increases at the rate of 0.05 cm/s. Find the rate at which its area is increasing when radius is 3.2 cm.

If water is poured into an inverted hollow cone whose semi-vertical angel is 30^0, and its depth (measured along the axis) increases at the rate of 1 cm/s. Find the rate at which the volume of water increases when the depth is 24 cm.

The volume of a sphere is increasing in volume at the rate of 3picm^(3)//sec . The rate of change of its radius when radius is 1/2 cm

The radius of an air bubble is increasing at the rate of (1)/(2) cm/s. At what rate is the volume of the bubble increasing when the radius is 1 cm?

A balloon, which always remains spherical has a variable radius. Find the rate at which its volume is increasing with the radius when the later is 10 cm.

The volume of a cube is increasing at the rate of 8 cm^(3) /s. How fast is the surface area increasing when the length of an edge is 12 cm?

The radius of the base of a cone is increasing at the rate of 3 cm/min and the altitude is decreasing at the rate of 4 cm/min. The rate of change of lateral surface when the radius is 7 cm and altitude is 24cm is (a) 108pic m^2//min (b) 54pic m^2//min (c) 27pic m^2//min (d) none of these