3. (Target C4) Two objects collide. One object has a mass of 50 kg and initial velocity Uli = -10x + 3y m/s The other has a mass of 150 kg and initial velocity U2i = -5x - 5y m/s After colliding, their velocities are Uif = -12.1x - 6.6y m/s and U2f = 2.4x - 1.8y m/s Was this collision elastic, or inelastic? Explain your reasoning. 4. (Target C5) A 150g pellet is fired at 75m/s directly upwards into a block of wood. The bullet becomes embedded in the block, and the system flies up to a height of 2m above the initial position of the block. What is the block's mass