A .30kg softball had a velocity of 15m/s at an angle of 35 degrees below the horizontal just before making contact with the bat. What is the magnitude of the change in momentum of the ball while it is in contact with the bat if the ball leaves the bat with a velocity of

Question

A .30kg softball had a velocity of 15m/s at an angle of 35 degrees below the horizontal just before making contact with the bat. What is the magnitude of the change in momentum of the ball while it is in contact with the bat if the ball leaves the bat with a velocity of 
a)20m/s, vertically downward and 
b) 20 m/s horizontally away from the batter and back toward the pitcher?

Please guide me towards the correct solution. For a) I tried 15sin35 and got 8.603 as the velocity and for b) I tried 15cos35 and got 12.287 as the velocity but i am not sure if that has to do with anything. What is the correct answer?