Answer:
The final velocity of 18 kg ball is
= 42.09 
Explanation:
Mass of first ball
= 18 kg
Mass of second ball
= 47 kg
Initial velocity of 18 kg ball
= 76 
Initial velocity of 47 kg ball = 0
Final velocity of 18 kg ball
= ??
Final velocity of 18 kg ball is given by the formula
= 
Put all the values in above formula we get
= 2 × 18 × 
= 42.09 
Thus, the final velocity of 18 kg ball is
= 42.09 