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!

Bullet and Pendulum

  1. Jun 17, 2007 #1
    1. The problem statement, all variables and given/known data
    An 16.2 g rifle bullet traveling 240 m/s buries itself in a 3.54 kg pendulum hanging on a 2.90 m long string, which makes the pendulum swing upward in an arc. Determine the horizontal component of the pendulum's displacement.


    2. Relevant equations

    I used the Y center of mass equation which is:
    Ycm= m1y1+m2y2/m1+m2 but i got 2.9


    3. The attempt at a solution
    Im stuck and dont know what else to do
     
  2. jcsd
  3. Jun 17, 2007 #2

    malawi_glenn

    User Avatar
    Science Advisor
    Homework Helper

    use conservation of (total) energy and momentum. Neglect the heat that the bullet will "create" when hitting the pendelum. You must use some trigometry also.
     
  4. Jun 17, 2007 #3

    Doc Al

    User Avatar

    Staff: Mentor

    Consider the interaction as having two stages:
    (1) The collision of bullet and pendulum--what's conserved?
    (2) The rise of the pendulum+bullet (post collision)--what's conserved?
     
  5. Jun 18, 2007 #4
    so i find the PE+KE=PE+KE for both parts

    or in other words

    .5MV2=mgh for both parts?
     
  6. Jun 18, 2007 #5

    malawi_glenn

    User Avatar
    Science Advisor
    Homework Helper

    Yes.

    First the energy is the kinetic energy of bullet. Then all energy will be potential energy of the pendelum and the bullet. (m1+m2)gh
     
  7. Jun 18, 2007 #6

    Doc Al

    User Avatar

    Staff: Mentor

    Not exactly. Different quantities are conserved in each part of the motion. For example: During the collision, mechanical energy is not conserved. What is?
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Bullet and Pendulum
Loading...