A stone is dropped into a quiet lake and waves move in circles at a speed of 4cm per second. At the instant, when the radius of the circular wave is 10 cm, how fast is the enclosed area increasing?

A stone is dropped into a quiet lake and ripples move in circles at the speed of 5 cm/sec. At the instant when the radius of circular ripple is 8cm, how fast is the enclosed area increases?

A stone is dropped into a quiet pond and waves move in circles outward from the place where it strikes, at a speed of 30 cm per second. At the instant when the radius of the wave ring is 50 m, the rate of increases in the area of the wave ring is

A stone is dropped into a quiet pond and waves move in circles outward from the place where it strikes, at a speed of 30 cm per second. At the instant when the radius of the wave ring is 50 m, the rate of increases in the circumference of the wave ring is

A stone is dropped into a quiet pond and waves move in circles outward from the place where it strikes, at a speed of 30 cm per second. At the instant when the radius of the wave ring is 50 mt, find the rate of increase in the area and in the circumference of the wave ring.

If the rate of change in the area of a circle is pi sq.cm/sec, then the rate of change in the radius of the circle when the radius is 10 cm is

If the rate of change in the area of a circle is it pi sq. cm/sec, then find the rate of change in the radius of the circle when the radius is 10cm.

The radius of the circular disc increases at a uniform rate of 0.025 cm per sec. The rate at which the area of the disc increases, when the radius is 15 cm is

The volume of a cube is increasing at a rate of 9 cubie centimeters per second. How fast is the surface area increasing when the length of edge is 10 cms?