A 9.0 x 10^-3 kg ball is attached to a 3.6 x 10^-2 mass (M) by string that passes through a hole in a horizontal frictionless surface. The ball travels in a circular path of radius 0.35 m. What is the speed of the ball?

Question

I know the answer is 3.7 m/s, but I'm not sure how to get to the answer :S

Answer 1

well,you know the tension in the string has to equal the weight in the center, and equal centripetal force.

3.6E-2* g= 9E-3*v^2/.35

solve for v.