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: Conservation of Energy Problem.

  1. Feb 28, 2009 #1
    A cart, initially at rest, slides down a frictionless ramp onto a horizontal frictionless surface which is a distance h below the original position of the cart. It then collides with the free end of a relaxed horizontal spring, the other end of which is fixed to a wall. As a result the spring compresses a distance D.

    Suppose now the initial height is changed to 2h. How far will the spring now compress?

    A) sqrt(2)D
    B) 2D
    C) 4D

    ------

    Initially: mgh = 0.5 k D^2

    Suppose: mg(2h) = 0.5 k (2D)^2

    So... the spring will now compress 4D. Is this correct?
     
  2. jcsd
  3. Feb 28, 2009 #2

    LowlyPion

    User Avatar
    Homework Helper

    Maybe rework your math again?

    And remember D is unknown.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook