A child of mass M holds onto a rope and steps off a platform. Assume that the initial speed of the child is zero. The rope has length R and negligible mass. The initial angle of the rope with the vertical is θo, as shown in the drawing.
a. Using the principle of conservation of energy, develop an expression for the speed of the child at the lowest point in the swing in terms of g, R, and cos θo
b. The tension in the rope at the lowest point is 1.5 times the weight of the child. Determine the value of cos θo.
