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

Elastic Potential Energy Problem

  1. Nov 13, 2011 #1
    1. The problem statement, all variables and given/known data
    A 1.2 kg spring laboratory cart is held against a wall. The spring constant is 65.0 N/m. The spring is compressed 8.0 cm when held against the wall. What is the compression of the spring when the cart's velocity is 42.0 cm/s?

    2. Relevant equations

    3. The attempt at a solution

    x=5.71 cm

    But the answer says 5.6 cm, so I think I did something wrong.
  2. jcsd
  3. Nov 13, 2011 #2
    Since the cart is starting out already compressed to 8cm, you would have to consider that initial displacement in your equation. Subtract the final elastic potential energy from the original (x=8cm) elastic potential energy on the right side. Do that and you should get 5.6cm.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook