1. Limited time only! Sign up for a free 30min personal 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!

Homework Help: Spring and Gravity Potential Energies

  1. Nov 12, 2007 #1
    1. The problem statement, all variables and given/known data
    A 2-kg block is dropped from a height of 0.4 m onto a spring force whose constant k is 1960 N/m. Find the maximum distance the spring will be compressed.

    2. Relevant equations

    3. The attempt at a solution
    both the initial and final kinetic energy should be 0 so we should get an equation like this:

    I can't find an expression to put in for value that only has x and no other unknown variables.
  2. jcsd
  3. Nov 12, 2007 #2


    User Avatar
    Homework Helper
    Gold Member

    The expression you have will work.

    Hint: Let the lowest point the block reaches be h=0m.
  4. Nov 12, 2007 #3
    so I would substitute 0 in for value to get x = .089 m, correct? Yeah, that's what I have been getting. However, my teacher told me the answer is 1.00 m. I am starting to wonder if he read off the wrong answer. Do you get .089 m too?
  5. Nov 12, 2007 #4


    User Avatar
    Homework Helper
    Gold Member

    I also get .089m. Check to make sure your numbers and units are correct. If they are, then I suggest talking to your teacher about it. Even teachers aren't perfect!:smile:

    Technically, the method we are using assumed the spring is compressed a negligible amount, but I think this is a reasonable assumption that wouldn't change the answer that much.
    Last edited: Nov 12, 2007
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook