# Homework Help: Volleyball Impulse and momentum problem

1. Oct 15, 2013

### bchat112000

can someone explain to me how to start on this problem

A volleyball is spiked so that its incoming velocity of +4.1 m/s is changed to an outgoing velocity of -18 m/s. The mass of the volleyball is 0.44 kg. What impulse does the player apply to the ball?

2. Oct 15, 2013

### jfizzix

The impulse $J$ is defined as
$\vec{J}\equiv \int_{t_0}^{t_f}dt' \vec{F}_{net} (t')$

From Newton's second law, the impulse is also equal to the change of momentum.

$\vec{J}=\vec{p}_f -\vec{p}_i =m\vec{v}_f -m\vec{v}_i$

If we know $m$,$\vec{v}_f$, and $\vec{v}_i$, we have all the information needed to figure out the impulse.