Question

A 0.060 kg ball hits the ground with a speed of -32m/s. The ball is in contact with the ground for 45 milliseconds and the ground exerts a +55 N force on the ball. What is the magnitude of the velocity after it hits the ground?
a. 9.3m/sB.12m/sC.41m/sD.73m/s

Answer 1

A:

Impulse is given by:

FΔt = Δp

We know the mass and velocity and we need the final velocity so lets break this down and isolate

FΔt = mv(final) - mv(initial)

Factor out m

FΔt = m(v(final) - v(initial))

FΔt / m = v(final) - v(initial)

Add v initial

(FΔt / m) + v(initial) = v(final)

(55x45ms / 0.060) - 32 = v(final)

v(final) = +9.25 m/s or 9.3