A pitcher throws a 0.5kg ball of clay at a 6kg block of wood. The clay sticks to the wood on impact and their joint velocity afterwards is 3m/s. What is the original speed of the clay? I know the answer is 39m/s but I have no idea how they come up with that

2 answers

momentum is conserved

the mass of the clay, times its velocity; is equal to the mass of the clay+block, times its velocity

0.5 * v = (6 + 0.5) * 3
39m/s