One can write v1f − v2f = ǫ (v2i − v1i) where ǫ takes a value between 0 (perfectly inelastic) and 1 (perfectly elastic) for most collisions. suppose two pucks sliding on frictionless ice collide head-on with a coefficient of restitution ǫ = 0.73. they have masses and initial velocities of m1 = 0.38 kg, m2 = 0.15 kg, v1i = 1 m/s, and v2i = −5 m/s. what is the velocity of puck 1 after the collision? answer in units of m/s.