A constant force of 5N acts for a 5 seconds on a mass of 5kg initially at rest. Calculate the final momentum?

A. 125kgm/s¹
B. 25kgm/s¹
C. 15kgm/s¹
D. 0kgm/s¹

Correct Answer:

Option B – 25kgm/s¹

Explanation

Impulse = momentum

Impulse = Force (f) × time (t)

Momentum = mass (m) × velocity (v)

∴ Ft = Final momentum – initial momentum

FT = mv – mu

Since it is initially at rest u = 0

∴ 5 × 5 = mv − m(0)

25 = mv

∴ Final momentum = 25kgms−¹