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 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 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 mt, find the rate of increase in the area and in the circumference of the wave ring.

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

The radius of a circular plate is increasing at the rate of 0.01 cm/sec when the radius is 12 cm. Then the rate at which the area increases 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.

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