1. PF Contest - Win "Conquering the Physics GRE" book! Click Here to Enter
    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!

Energy- Spring Compression

  1. May 11, 2015 #1
    1. The problem statement, all variables and given/known data
    Students in a physics class set up an experiment to examine the behavior of springs being compressed under various conditions. In the first trial of the experiment, students released a 1.5 kg block from rest at the top of a ramp. The block slid down the ramp, across a horizontal surface, and then collided with an uncompressed, massless spring. Students attached a marker to the spring so they could see how far it was compressed in bringing the block to rest. All surfaces in trial 1 were effectively frictionless.
    In trial 2, the block was dropped from the same height directly above an identical spring. This spring was placed such that its bottom had the same height as the spring in trial 1 (as shown in the diagram). Again the students recorded the maximum compression of the spring in bringing the block to rest. Indicate which of the two springs experienced a greater compression in bringing the block to rest.

    2. Relevant equations
    Eg = mgh
    Esp = 1/2kx2

    3. The attempt at a solution
    Each block will have a potential energy that is conserved as elastic energy. The blocks have the same mass and the springs have the same k. For each block and spring, mgh = 1/2kx2, but I'm not sure about the h for Trial 2. Would it be the same as Trial 1?
  2. jcsd
  3. May 11, 2015 #2


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    Try assuming that in both cases the spring is compressed some amount (say 50%?) after the collision. Draw that and work out the height that you would use to calculate the PE that has been converted into energy stored in the spring. Can they be the same?
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted