Question

A body of mass 10 kg falls from a height of 20 m to 8 m. Calculate: (i) the loss in potential energy of the body, (ii) the total energy possessed by the body at any instant? (Take g = 10 ms-2).

April 18, 2024

Answer

Mass = 10Kg

Fall in height = 20 – 8 = 12m

(i) Loss in potential energy = mg(h₁ – h₂)

Substituting the vales in formula we get,

Loss in potential energy = 10 x 10 x 12 = 1200 J

(ii) Total energy remains constant for free fall.

Total energy = P.E + K.E

So, at height 20 m, K.E = 0

Therefore total energy = P.E + K.E

Total energy = mgh + 0

= 10 x 10 x 20 = 2000 J

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