Volleyball Impulse and momentum problem

[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?

 

[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.