A .37kg bullet travelling at 719m/s strikes a 2.4kg block of wood sitting at rest. The bullet is embedded in the block. Assuming no friction, what is the velocity of the block?

Question

A .37kg bullet travelling at 719m/s strikes a 2.4kg block of wood sitting at rest. The bullet is embedded in the block. Assuming no friction, what is the velocity of the block?

Answer 1

Hi Chloe B.,

I love that part about "no friction". What stopped the bullet, then?

Anyway, the intent of the question is clear -- just solve as a conservation of momentum problem. The bullet has all the initial momentum, and the (block+bullet) has the final momentum. OK?

Since it is a velocity problem, don't forget to add "in the direction of travel of the bullet before impact". Otherwise your answer would be a speed, not a velocity!!

Oh, and you should probably also add, "if the block was free to move". 'Cause if it was up against a wall, for example, it isn't going ANYwhere!

-- Cheers, -Mr. d.