Calculating Bullet Speed: Pendulum Physics Homework Problem Solution

[BugsSport]

Homework Statement

I have to calculate the speed of a bullet, based on the amount of displacement created when the bullet becomes lodged in the log.
I have the horizontal displacement, the weight of the log, and the length of the string.

Homework Equations

I'm not sure how to set this up so I don't know what equations to use yet.

The Attempt at a Solution

I calculated the horizontal displacement and have enough information to finish the problem, but I'm not sure which equations to use. Any start is appreciated, thanks.

 

[LowlyPion]

KE = PE

The ½mV² of the bullet becomes the mgh of the log displacement.

You know L and θ apparently so ...

 

[BugsSport]

I just figured it out. Thanks for the response though

 

[BugsSport]

Just for future reference, this page helps a lot in pendulum problems
http://www.rowan.edu/colleges/lasold/PhysicsAndAstronomy/LabManual/labs/EnergyInAPendulum.pdf