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 colliding into spring

  1. Jan 25, 2010 #1
    1. The problem statement, all variables and given/known data

    A 4kg block resting on frictionless surface is attached to spring of k=100n/m. A 2g bullet is fired at 100m/s at the block. What is the period and amplitude of oscillations?



    2. Relevant equations

    1/2mv2 = kinetic energy
    1/2kx2 = elastic energy
    2 x pi x square root (mass/k) = period

    3. The attempt at a solution

    No answer choices given, just seeing if my thought process is valid.

    First, period. 2 x pi x square root (4/100) = 2 x pi x 2/10 = 4pi/10 = approx. 1.2

    Next, amplitude. 1/2 (.002g) (100m/s2) = 1/2 100n/m x2
    therefore, x equals out to .45, or 45 cm?



    Does this make sense, I think I have the period right, but one of my friends got 1 cm for the amplitude and another one of my friends got 0.83 seconds for the period. Any ideas?


    Thanks
     
  2. jcsd
  3. Jan 26, 2010 #2
    There's been a mistake.
    You took an inelastic collision for a completely elastic one.Instead conserve momentum to find velocity of bullet-block system and then proceed for momentum.
     
  4. Jan 26, 2010 #3
    That makes great sense. Thanks
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Bullet colliding into spring
  1. Bullets and springs (Replies: 32)

Loading...