The velocity of a body of mass 10kg increases from 4 m/s to 8 m/s when

1.	The velocity of a body of mass 10kg increases from 4 m/s to 8 m/s when a force acts on it for 2s. a) What is the momentum before the force acts? b) What is the momentum after the force acts? c) What is the gain in momentum per second? d) What is the value of the force?
Answer» Mass of the body = 10kg Initial velocity, u = 4 m/s Final velocity, v = 8 m/s Time, t = 2s a) Momentum before the force acts, p₁ = mu = 40 kg.m/s b) Momentum after the force acts, p₂ = mv = 80 kg.m/s c) Gain in momentum for 2s = p₂ – p₁ = 40 kg.m/s Gain in momentum per second = 40/2 = 10 kg.m/s d) Acceleration, a = (v-u)/t = 2 m/s^₂ Force = ma = 20N

The velocity of a body of mass 10kg increases from 4 m/s to 8 m/s when a force acts on it for 2s. a) What is the momentum before the force acts? b) What is the momentum after the force acts? c) What is the gain in momentum per second? d) What is the value of the force?

Answer»

Mass of the body = 10kg

Initial velocity, u = 4 m/s

Final velocity, v = 8 m/s

Time, t = 2s

a) Momentum before the force acts, p₁ = mu = 40 kg.m/s

b) Momentum after the force acts, p₂ = mv = 80 kg.m/s

c) Gain in momentum for 2s = p₂ – p₁ = 40 kg.m/s

Gain in momentum per second = 40/2 = 10 kg.m/s

d) Acceleration, a = (v-u)/t = 2 m/s^₂

Force = ma = 20N