An object weighing 40 kg rises to a height of 5 m above the ground. What is its potential energy? If you let an object fall, find the kinetic energy when it is in the middle.
Gravitational mechanical energy is given by the expression, W = mgh Where, h = Vertical displacement = 5 m, m = Mass of the item = 40 kg g = Acceleration because of gravity = 9.8 m s^{-2}s−2 ∴ W = 40 × 5 × 9.8 = 1960 J. At half-way down, the mechanical energy of the item is going to be 1960/2 At this time, the item has an equal quantity of potential and K.E. This can be due to the law of conservation of energy. Hence, half-way down, the K.E. of the item can be 980 J.
2 j, 5 j.
2, 5
