The string of pendulum of length ' L ' is displaced through 90^ from the vertical and released. Then the maximum strength of the string in order to withstand the tension, as the pendulum passes through the mean position is ( m = mass of pendulum, g = acceleration due to gravity)

Step-by-step solution

By conservation of energy aligned & K.E. = 1 2 mv ^2= mg l & v = 2 ~g l aligned The forces acting on the pendulum at mean position are tension in string, centripetal force and weight of pendulum. aligned & T - mv ^2 l = mg & ~T - m ( 2 ~g l )^2 l = mg & ~T =3 mg aligned ...[From (i)]