Question

An average force of 1200 newton acts on a 0.5 kg steel ball during a collision lasting 25 m seconds if the force is in the direction opposite of the initial velocity of 14 m per second then the final speed of the steel ball will be

Answer 1

F = force applied = - 1200 N

v₁ = initial velocity = 14 m/s

v₂ = final velocity = ?

m = mass = 0.5 kg

t = time duration = 25 ms = 0.025 sec

using impulse-change in momentum equation

F t = m (v₂ - v₁ )

- 1200 (0.025) = (0.5) (v₂ - 14)

v₂ = - 46 m/s

hence the final speed is 46 m/s in same direction as the force