For the Clubhead:
m1 = 0.215 kg
initial velocity(u1) = 55 m/s
Final velocity (v1) = 42 m/s
For the Ball:
m2 = 0.046 kg
initial velocity (u2) = 0 m/s
final velocity (v2) = x m/s
Using the law of conservation of momentum:
m1u1 + m2u2 = m1v1 + m2v2
replacing the variables
(0.215)(55) + (0.046)(0) = (0.215)(42) + (0.046)(x)
11.825 = 9.03 + 0.046x
0.046x = 2.795
x = 2.795 / 0.046
x = 60.76 m/s
Therefore, the ball will be projected at a velocity of 60.76 m/s