Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Pendulum Physics problem

  1. Nov 24, 2008 #1
    1. The problem statement, all variables and given/known data
    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.

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

    3. 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.
  2. jcsd
  3. Nov 24, 2008 #2


    User Avatar
    Homework Helper

    KE = PE

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

    You know L and θ apparently so ...
  4. Nov 24, 2008 #3
    I just figured it out. Thanks for the response though
  5. Nov 24, 2008 #4
    Just for future reference, this page helps a lot in pendulum problems
    http://www.rowan.edu/colleges/lasold/PhysicsAndAstronomy/LabManual/labs/EnergyInAPendulum.pdf [Broken]
    Last edited by a moderator: May 3, 2017
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook