Soccer - What was the impulse on the soccer ball

[gansta344u]

Homework Statement

A 0.40 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 units of kg · m/s.

2. Homework Equations
M(v)f-M(v)i=impulse

The Attempt at a Solution

i did (.4kg)(24m/s)-(.4kg)(18m/s) and i got it wrong so if u can please help

 

[LowlyPion]

Homework Statement

A 0.40 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 units of kg · m/s.

2. Homework Equations
M(v)f-M(v)i=impulse

The Attempt at a Solution

i did (.4kg)(24m/s)-(.4kg)(18m/s) and i got it wrong so if u can please help

The key here is direction.

If it comes in at 18m/s and reverses then it returns at -24m/s.

-24 - 18 = -42

 

[The Bob]

The key to this is directions. Choose one and then all velocities are either positive or negative relative to that. Does that help?

The Bob

P.S. It's not my night; second after post, apologies once again.