A small ball of mass 50 g is suspended from a string of length 66 cm and whirled in a circle lying in the horizontal plane.

A small ball of mass 50 g is suspended from a string of length 66 cm and whirled in a circle lying in the horizontal plane. If the string makes an angle of 21◦ with the vertical, find the centripetal force experienced by the ball. The acceleration of gravity is 9.8 m/s2 .