Question

A particle of mass m is attached to a light string of length l, the other end of which is fixed. Initially the string is kept horizontal and the particle is given an upward velocity v. The particle is just able to complete a circle.
(a) The string becomes slack when the particle reaches its highest point.
(b) The velocity of the particle becomes zero at the highest point.
(c) The kinetic energy of the ball in initial position was 1/2 mv² =mgl
(d) The particle again passes through the initial position

Answer 1

(a) The string becomes slack when the particle reaches its highest point. 
(d) The particle again passes through the initial position