Question

Someone fires a 0.04 kg bullet at a block of wood that has a mass of 0.5 kg. (The block of wood is sitting on a frictionless surface, so it moves freely when the bullet hits it). The wood block is initially at rest. The bullet is traveling 300 m/s when it hits the wood block and sticks inside it. Now the bullet and the wood block move together as one object. How fast are they traveling? Please show your work

Answer 1

The momentum of the wood and the bullet is equal to the momentum of the bullet before it hits the wood = 0.04 x 300 = 120 kg m/sHence (0.5 + 0.04)*v = 120 kg m/s, v = 120 kg m/s / 0.54 kg = 222.2 m/s3) Force = rate of change of momentum = 0.16(38+44)/0.002 = 6560 N