If a constant force acts on a body, the rate of change of its momentum is proportional to the force. If the force doubles, what happens to the rate of momentum change?

• A. Doubles
• B. Increases
• C. Halves
• D. Remains the same

Answer: (A)

The rate at which momentum changes is exactly equal to the applied force. This is Newton’s second law in momentum form: dp/dt = F. If the force doubles, the rate of momentum change doubles as well, so momentum increases twice as fast. Since dp/dt is directly proportional to F for a constant force, there’s a one-to-one increase with force, not just a vague increase, a halt, or a reduction.