Two point masses M are connected to the light rod of length L and it is free to rotate in vertical plane as shown. Calculate the minimum horizontal velocity given to lower mass M so that it completes the circular motion is vertical plane.
√48gL5
By energy conservation
Ki+Ui=Kf+Uf⇒12mV2+12mV24=mg(2l)+mg(4l)⇒v=√48gl5