A frictionless pendulum is made with a bob of mass 19.7 kg. The bob is held at height = 0.934 meter above the bottom of its trajectory, and then pushed forward with an initial speed of 2.93 m/s. What amount of mechanical energy does the bob have when it reaches the bottom?

Answer 1

According to the law of conservation of energy in frictionless case the total mechanical energy of the pendulum is constant
E = mgh +mv²/2 = 19.7•9.8•0.934 + 19.7•2.93²/2 = …

Answer 2

therefore the answer is 265 J