# What impulse was delivered to the ball by the player?

1. Nov 16, 2007

### missashley

1. The problem statement, all variables and given/known data

A 0.47 kg soccer ball approaches a player horizontally with a velocity of 18 m/s to the north. The player strikes the ball and causes it to move in the opposite direction with a velocity of 24 m/s.

What impulse was delivered to the ball by the player? Answer in kg*m/s

2. Relevant equations

impulse = change in momentum
momentum = mv

3. The attempt at a solution

0.47((24-(-18)) = 19.74 kg*m/s

or would it be

0.47(24-18) = 2.82 kg*m/s

i'm lost

2. Nov 16, 2007

### Bill Foster

The change in momentum will be

$$mv_1-mv_2 = m(v_1-v_2)$$

Now keep in mind these are vectors. So one will be a negative number...

$$.47 kg (18 - (-24) \frac{m}{s})$$

3. Nov 16, 2007

### missashley

oops i meant - 2.82, it says it wrong

4. Nov 16, 2007

### missashley

Nevermind I got it

0.47(-24-18) = -19.74 thats the answer