CBSE Class 9 Answered

Gravitational potential energy is given by the expression,

W = m g h

where,

h = Height above the ground = 10 m

m = Mass of the object = 50 kg

g = Acceleration due to gravity = 10 ms-2

W = 50 × 10 × 10 = 5000 J.

At half-way down, the potential energy of the object will be,   

At this point, the object has an equal amount of potential and kinetic energy. This is due to the law of conservation of energy. Hence, half-way down, the kinetic energy of the object will also be 2500 J.