A body has a free fall from a height of 20 m After falling through a distance of 5 m then body would...........

General Science (NDA) Physics

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A body has a free fall from a height of 20 m. After falling through a distance of 5 m, then body would

lose one-fourth of its total energy

lose one-fourth of its potential energy

gain one-fourth of its potential energy

gain three-fourth of its total energy

Explanation:

Initial gravitational potential energy of two body
U₁ = mgh = 20mg [ $\because$ h = 20m]
$\therefore$ Initial total energy of the body
E = U₁ + K ₁ = U₁ +0 = U₁ = 20 mg
After falling through 5 m, new potential energy is
U₂ = mgh' = (20 − 5) = 15mg
$\therefore$ Loss in potential energy
$\Delta$ U = U₁ − U₂ = 20mg −15 mg = 5mg
i.e. 1/4 of its potential energy.