A ball on the end of a string is moving in a horizontal circle. If the centripetal acceleration of the ball is 12 m/s2, while it is travelling at 3.0 m/s, what would the acceleration be if its speed increased to 4.0 m/s. Assume that the radius of rotation does not change.

Answer 1

Ac = v^2/r
if you increase v, then v^2 increases by the square of the ratio

new Ac = (16/9) old Ac
= (16/9)12 = 21.3 m/s^2