If the momentum of a body increases from 10 units to 25 units in 5 sec, then…

Newton's second law defines force as the rate of change of momentum, expressed as F = Δp / Δt, where Δp is the change in momentum of the body and Δt is the time interval over which that change occurs.

1. Identify the given values: initial momentum p1 = 10 units, final momentum p2 = 25 units, time interval Δt = 5 seconds.

2. Find the change in momentum: Δp = p2 − p1 = 25 − 10 = 15 units.

3. Apply Newton's second law: F = Δp / Δt = 15 / 5 = 3 units.

Cross-check: by the impulse–momentum theorem, impulse J = F × Δt should equal the momentum change. Here, 3 units × 5 seconds = 15 units, which matches Δp computed above, confirming the result.

Hence, the force acting on the body is 3 units.