A sphere of mass ms rests on the smooth parabolic surface. Determine the normal force it exerts

Question:

A sphere of mass ms rests on the smooth parabolic surface. Determine the normal force it exerts on the surface and the mass mB of block B needed to hold it in the equilibrium position shown.

Given:
ms = 4 kg
a = 0.4 m
b = 0.4 m
θ = 60 deg
g = 9.81 m/s2