A hockey puck of m m = 90 g is attached to a string that pes through a hole in the center...?

A hockey puck of m m = 90 g is attached to a string that pes through a hole in the center of a table. The hockey puck moves in a circle of radius r = 0.95 m. Tied to the other end of the string, and hanging vertically beneath the table, is a m M = 1.10 kg. uming the tabletop is perfectly smooth, what speed must the hockey puck have if the mass M is to remain at rest? Please help.