A body of mass 5 kg is moving with a momentum of 10 kg m s⁻¹. Now a force of 2 N acts on the body in the direction of its motion for 5 s. The increase in the Kinetic energy of the body is _________ J.
Physics · Circular Motion
JEE Mains 8 April 2023 Shift 2 Evening Shift

Question

A body of mass 5 kg is moving with a momentum of 10 kg m s⁻¹. Now a force of 2 N acts on the body in the direction of its motion for 5 s. The increase in the Kinetic energy of the body is _________ J.

Physics · Circular Motion

JEE Mains 8 April 2023 Shift 2 Evening Shift

G1 Physics · Accepted Answer

Initial momentum: p₁ = 10 kg m s⁻¹ Impulse due to force: J = Ft = 2×5 = 10 kg m s⁻¹ Since force acts in the direction of motion: p₂ = p₁ + J = 20 kg m s⁻¹ Kinetic energy in terms of momentum is K = p²/(2m) With m = 5 kg: K₁ = 10²/(2×5) = 10 J K₂ = 20²/(2×5) = 40 J Increase in kinetic energy: ΔK = 40 − 10 = 30 J Final value: 30