# Momentum problem

A 11.0-g bullet is fired horizontally into a 108 g wooden block that is initially at rest on a frictionless horizontal surface and connected to a spring of constant 154 N/m. If the bullet-block system compresses the spring by a maximum of 76.0 cm, what was the velocity of the bullet at impact with the block.

what i did first was i set F=kx to find the force the bullet block system applied to the spring.

after solving for F, i couldnt find a way to relate force to the momentum equation
m1v1i=(m1+m2)vf

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Doc Al
Mentor
what i did first was i set F=kx to find the force the bullet block system applied to the spring.
Instead of worrying about the force, consider the energy stored in the spring.

ok so how do i set it up

Doc Al
Mentor
Think of the problem as having two parts:
(1) The collision itself. What's conserved during the collision?
(2) The compression of the spring after the collision. What's conserved here?