Impulse

[staceyrho]

In this question im being thrown off by the different directions?

A 0.37kg soccer ball approaches a player horizontally with a velocity of 15 m/s to the north. The player strickes the ball and causes it to move in the opposite direction with a velocity of 21 m/s. What impulse was delivered to the ball by the player?

 

[daon]

impulse = force * (change in time) = mass * (acceleration * (change in time)) = mass * (change in velocity)

mass = 0.37kg
change in velocity = (+15 - (-21))

This problem is one-dimentional, you don't need the direction information. The key word is "opposite" direction which means one velocity vector should ahve a negative in front.

 

[staceyrho]

Thanks for the help!!!!

 

[daon]

Thanks for the help!!!!

Im sorry.. technically should be (-21-15) as it is a vector quantity and going south which intuitively is "negative".