Question

A body of mass 10 kg is moving with a velocity 20 m s^-1. If the mass of the body is doubled and its velocity is halved, find:
(i) the initial kinetic energy, and
(ii) the final kinetic energy.

April 23, 2024

Answer

Initial Mass = 10 kg and

Final mass = 2 × 10 kg = 20 kg

Initial Velocity = 20 m s^-1

Changed velocity v₂ = 20 / 2 = 10 m s^-1

(i) Initial kinetic energy = $1 \over 2$ × mass × (velocity)²

= $1 \over 2$ × 10 × (20)²

= 2000 J

(ii) Final kinetic energy = $1 \over 2$ × 20 × (10)²

= 1000 J

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