Humpback whales sometimes catch fish by swimming rapidly in a circle, blowing a curtain of bubbles that confuses a school of fish and traps it in a small area, where the whales can easily catch and eat them. Suppose a 25,000-kg humpback whale swims at 2.0 m/s in a circle of radius 8.2 m. What centripetal force must the whale generate?

1.2 x N

Explanation:

The centripetal force of a body moving in a circle is given by:

Centripetal force =

where M = mass of the object, v = velocity with which the object is moving, and r = radius of the circle.

In this case, M = 25,000 kg, v = 2.0 m/s, and r = 8.2 m. Hence;

Centripetal force generated by the whale = 25,000 x 2^2/8.2

                                            = 12,195.12 N = 1.2 x N to two significant digits.