The two disks A and B have a mass of 3 kg and 6 kg, respectively. They collide with the initial velocities shown. The coefficient of restitution is e=0. 75. (vₐ)₁ =5m/s, (v_b)₁ = =8m/s. What is the final velocity of disk A after the collision?
a) 1 m/s
b) 4 m/s
c) 7 m/s
d) 10 m/s