Answer:
12m/s
Explanation:
Given parameters:
M1 Â = 1kg
M2 Â = 5kg
V = 2m/s
Unknown:
Speed of the ball thrown = ?
Solution:
In a system, the momentum must be conserved. Since we are dealing with an elastic collision:
     M1 V1  +  M2 V2  = v(M1 + M2)
So;
    1 x V1 + (5 x 0) = 2(1 + 5)
       V1  = 12m/s