A bullet is fired into a block of wood sitting on a block if ice. The bullet has an initail velocity of 500m/s

Question

and a mass of 0.005 kg. The wooden block has a mass of 2kg and is initially at rest. The bullet remains embedded in the block of wood afterward.

a. Assuming that the momentum is conserved, find the final velocity of the block of wood (and bullet) after the collision.

b. What is the magnitude of the impulse that acts on the block of wood in this process?

c. Does the change in momentum of the bullet equal that of the block of wood? Explain.

Answer 1

a.  Initial Momentum = Final Momentum

mb* vb = (mb+ mw) * vf

vf = mb* vb / (mb+ mw)

vf = 1.247 m/s

b. impulse = mb (vb-vf)

= 2.494 kg m/s

c.  no, momentum is a vector quality.  They are equal in magnitude, but in opposite directions.

Answer 2

Remo knows the formulas, but in a real world scenario the variables would have dramatic effects on the outcomes. For instance - a soft metal slug hitting an aged hardwood 1x4 block would have different outcomes than an armor piercing bullet hitting a fresh softwood 4x4 block... Even the resistance of the ice could become an issue, is it slightly melting ice (water between the ice and the block would be more resistance), something like pykrete, or very smooth ice?

I got one more - What if the block spins?