posted by opp .
A 0.01-kg baseball traveling in a horizontal direction with a speed of 11 m/s hits a bat and is popped straight up with a speed of 15 m/s.
(a) What is the change in momentum (magnitude and direction) of the baseball?
They already told you that the direction change is 90 degrees, from horizontal to "up". Use the Pythagorean Theorem for the magnitude.