**A horizontal force of 310 N is exerted on a 2.0-kg ball as it rotates uniformly in a horizontal circle of radius .90 m. Calculate the speed of the ball.**

**Answer**:

F = m.w^2.r

where,

F= force = 310 N

m = mass = 2 kg

r = 0.9 m

w = angular velocity in radians per second, speed of the ball can be calculated from w as v=w.r

Rearragning the force expression, we have

w^2 = F/mr = 172.22

So w = 13.12 and v= wr = 11.81 m/s