# Bullet shot into pendulum - conservation of energy

## Homework Statement

A 27-g rifle bullet traveling 230m/s buries itself in a 3.3-kg pendulum hanging on a 2.9-m-long string, which makes the pendulum swing upward in an arc.
Determine the vertical and horizontal components of the pendulum's maximum displacement.
x=? and h=?

## Homework Equations

v= (m+M)/m * sqr root (2gh)

## The Attempt at a Solution

I just expanded on the above equation and derived several others ..dont know where to go next.. L = length of string ; M=block's mass ; h=max height ; x=distance on x axis ; m=bullet's mass
v= (m+M)/m * sqr root (2gh)
(v* (m/m+M)^2)/(2g)=h
h= L(1-cos theta)
cos-1 theta(-1 ((h/L)-1) = theta
L sin theta = x
EDIT: sorry nicksauce. I have now included the question.

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## Answers and Replies

nicksauce
Science Advisor
Homework Helper

What exactly is the question here? I see no question marks in your post.

HallsofIvy
Science Advisor
Homework Helper

I would be inclined to use "conservation of Energy". You can calculate the kinetic energy of the bullet and you can take the potential energy to be 0 at the bottom of the arc. At the highest point the kinetic energy of both is 0 so all energy has be changed to potential energy. From the potential energy you can find the height.

I think this will get a better response in the physics section so I am going to move it there.