A small block of mass m slides along a smooth frictional track as shown in the figure. If it starts from rest at P , what is the resultant force acting on it at Q ?

Step-by-step solution

From energy conservation, M g 4 R = 1 2 m v 2 ⇒ v = 8 R g At θ , N = m v 2 R ⇒ N = m R × 8 g R = 8 m g So net force at θ , F n e t = N 2 + m g 2 = 65 m g