This problem is baffling me. A 3kg puck revolves in a circle on a frictionless table at the end of a 50cm long string. The puck's angular momentum is 3kg (m^2/s). What is the tension in the string? This what I did L= mrv therefore 3kg*.25m*v = 3kgm^2/2 v=4m/s F=(mv^2)/r (3kg*16m/s)/(.25m) = 192N is this right?