I have several problems like this and am confused at how to solve. A small box of mass 9 g is initially at some angle with respect to the ploar axis of a spherical dome of radius 3 m as shown in the figure. Starting from rest, the box slides down along the frictionless spherical surface. The acceleration due to gravity is 9.8 m/s^2. Find the critical angle at which the box leave the surface of the dome. Answer in units of degrees.