Impulse Problem?

Question

A .42 kg soccer ball approaches a player horizontally with a velocity of 17m/s to the north. The player strikes the ball and causes it to move in the opposite direction with a velocity of 23m/s. What impulse was delivered to the ball by the player? Answer in units of KG x M/s.

Answer 1

Impulse is "Definition: Impulse is defined as a force multiplied by the amount of time it acts over. In calculus terms, the impulse can be calculated as the integral of force with respect to time. Alternately, impulse can be calculated as the difference in momentum between two given instances" [See source.]

So assume p0 = mv0 and p1 = mv1 are the two momenta for instances 0 and 1. Then I = p1 - p2 = m(v1 - v0); where m = .42 kg and v1 = 23 m/sec and v0 = -17 m/sec (minus sign means the approaching ball was going directly opposite to the direction of the kicked ball). You can do the math.

Physics lesson...when mass is a fixed value, the impulse is determined by the velocity changes. And velocity is a vector having both magnitude and direction. That's why, in your case, the two magnitudes were added.