Ballistics Pendulum Homework: Solving for Velocity After Bullet Emerges

[12boone]

Homework Statement

A 23 g bullet traveling 235 m/s penetrates a 3.8 kg block of wood and emerges cleanly at 195 m/s.

If the block is stationary on a frictionless surface when hit, how fast does it move after the bullet emerges?

Homework Equations

(1) mv= (m+M)v'

momentum before= momentum after

(2) 1/2(m+M)v'^2 = (m+M)gh

The Attempt at a Solution

I attempted to solvethis using these two equations and I received an answer for 1.14 m/s and 230 m/s. I am having a lot of trouble even determining how to start this problem. I don't want a quick easy answer but I would like help working through it! Thank You!

 

[tiny-tim]

A 23 g bullet traveling 235 m/s penetrates a 3.8 kg block of wood and emerges cleanly at 195 m/s.

If the block is stationary on a frictionless surface when hit, how fast does it move after the bullet emerges?
…
(1) mv= (m+M)v'

momentum before= momentum after

(2) 1/2(m+M)v'^2 = (m+M)gh
…
I attempted to solvethis using these two equations …

Hi 12boone!

However did you use equation (2)?

Equation (1) should be enough.

Try again!