The collar, which has a weight of 3 lb, slides along the smooth rod lying in the horizonta...

The collar, which has a weight of 3 lb, slides along the smooth rod lying in the horizontal plane and having the shape of a parabola r = 4/(1 - cos θ), where θ is in radians and r is in feet. If the collar’s angular rate is constant and equals  determine the tangential retarding force P needed to cause the motion and the normal force that the collar exerts on the rod at the instant θ = 90°.