Question

A body of mass 10 kg is moving with a velocity of 20 m/s. The mass of the body is doubled and velocity in halved. Its initial kinetic energy is ______.

Options

• 200 J

• 4000 J

• 2000 J

• 1000 J

Answer 1

A body of mass 10 kg is moving with a velocity of 20 m/s. The mass of the body is doubled and velocity in halved. Its initial kinetic energy is 2000 J.

Explanation:

Initial kinetic energy = \[ \frac{1}{2} \times 10 \times (20)^{2} = 2000 \] J. The other options come from wrong substitution of the changed mass/velocity or from misreading the question.