1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Ballistic Pendulum Rifle

  1. Nov 4, 2008 #1
    The problem:

    [​IMG]

    A rifle bullet of mass m = 0.03 kg traveling at vb = 240 m/s collides with and embeds itself in a pendulum of mass M = 2.88 kg, initially at rest and suspended vertically by massless strings of length L = 2 m.

    How high does the pendulum-bullet combination rise after the collision?

    I don't know the process for solving this equation, so help would be appreciated.
     
  2. jcsd
  3. Nov 4, 2008 #2

    Borek

    User Avatar

    Staff: Mentor

    Energy preservation. Kinetic gets converted into potential.
     
  4. Nov 4, 2008 #3
    Okay, so I need to use PE = mgh. I don't understand what I do with the velocity of the bullet and how to setup the problem, if I could get a little more guidance it would help me out

    Thanks.
     
  5. Nov 4, 2008 #4

    Borek

    User Avatar

    Staff: Mentor

    What is formula for kinetic energy?
     
  6. Nov 4, 2008 #5
    We did this the other day, except we just manipulated the formulas instead of working with actual values.
    I am going to attempt to make sense of what I have for that note, so you may hear from me soon...
     
  7. Nov 4, 2008 #6
    KE = (1/2)mv2
     
  8. Nov 4, 2008 #7

    Borek

    User Avatar

    Staff: Mentor

    Is there something you still don't know? Just beware which mass is which - ballistic pendulum mass after hit is that of pendulum PLUS bullet.
     
  9. Nov 4, 2008 #8
    I don't understand what it is I do with the equation for Kinetic Energy, I'm supposed to find the height of the bullet-pendulum system after the bullet hits the pendulum.
     
  10. Nov 4, 2008 #9

    Borek

    User Avatar

    Staff: Mentor

    h as of mgh.
     
  11. Nov 4, 2008 #10

    Doc Al

    User Avatar

    Staff: Mentor

    This problem is best solved in two stages:
    (1) The collision itself. You need to find the speed of the block+bullet immediately after the collision. Hint: Energy is not conserved, but something else is.
    (2) The rising of the pendulum after the collision. Here you do use energy conservation, as Borek explains.
     
  12. Nov 4, 2008 #11

    Borek

    User Avatar

    Staff: Mentor

    Do we have an emoticon for selffishslapping? :blushing:
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Ballistic Pendulum Rifle
  1. Ballistic Pendulum (Replies: 0)

  2. Ballistic pendulum (Replies: 2)

  3. Ballistic Pendulum (Replies: 1)

  4. Ballistic Pendulum (Replies: 8)

  5. The Ballistic Pendulum (Replies: 2)

Loading...