Efficiency in Physics

Question

A 200 g pendulum bob is raised 22 cm above its rest position. The bob is released, and it reaches its maximum speed as it passes the rest position. Calculate its maximum speed if the efficiency is 94%.

Answer 1

mv_max²/2 = 0.94mgh

v_max²/2 = 0.94gh

v_max = √[2(0.94gh)]

Plug in

g = 980 cm/s²

h = 22 cm

and get v_max in cm/s.