What was the original speed of the clay (in m/s)?

Question

A pitcher throws a 0.70 kg ball of clay at a 3.0 kg block of wood. The clay sticks to the wood on impact, and their joint velocity afterward is 1.1 m/s. What was the original speed of the clay (in m/s)?

Answer 1

By conservation of momentum of the system

Momentum before = 0.70 v (v = original speed of clay)

Momentum after = 3.70 x 1.1

So 0.70 v = 3.70 x 1.1, giving v = 5.8 m/s