Question

A cube of mass M starts at rest from point 1 at a height 4R, where R is the radius of the circular track. The cube slides down the frictionless track and around the loop. Find the force which the track exerts on the cube at point 2.

(a) The bob of a pendulum is released from a horizontal position. If the length of the pendulum is L, what is the speed with which it arrives at the lower most point, given that it dissipates its 10 % energy against air resistance? (b) If the same bob is releases as shown in the figure, find the speed at the lowermost point if it dissipates no energy.