Answer:
2.22m/s
Explanation:
Given parameters:
M1 Â = 60kg
M2 Â = 75kg
V1 Â = 0m/s
V2 Â = 4m/s
Unknown;
Velocity after collision  = ?
Solution:
To solve this problem, we must understand that the momentum before and after collision of the bodies must be the same;
   M1 V1  + M2 V2  = v(M1 + M2)
So;
    60 x 0  +  75 x 4  = v (60 +75)
         300  = 135v
          v = 2.22m/s