A 2-kg ball attached to a string of length 1.5 m moves in a horizontal circle as a conical pendulum (Figure). The string makes an angle q = 30o with the vertical.

(a) Show that the angular momentum of the ball about the point of support P has a horizontal component toward the center of the circle as well as a vertical component, and find these components.

(b) Find the magnitude of dL/dt, and show that it equals the magnitude of the torque exerted by gravity about the point ofsupport.

1.5 m 30: 2 kg