1. The problem statement, all variables and given/known data A .30 kg ball with initial velocity of 21i - 1.3j colldes with a wall. The wall exerts a force of -155i N on the ball and its final horizontal component of velocity is -11i m/s. (a) Find the vertical velocity component. (b) Find the total change in momentum. (c) How long was the ball in contact with the wall? 2. Relevant equations change in momentum = impulse = Ft 3. The attempt at a solution I think my main problem is im not sure if this is a conservatoin of momentum problem or not - is momentum conserved after the collision with the wall? Im having a hard time relating the 155 N force applied from the wall to the ball. I know that if I can find the vertical component of velocity after hitting the wall, I can easily find the change in momentum (part b) by: m (vf - vi) where vf and vi are the overall resultant velocity vectors. and i know that if i get that i can set it equal to Ft to find the time in contact with the wall (part c) but i cannot figure out part a. can someone please help. thanks.