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: Conservation of Energy (Spring + Kinetic)

  1. Nov 20, 2005 #1


    User Avatar

    Tonight I've got so many hard problems...

    A 3.0 kg mass slides across a frictionless surface and collides against a spring bumper with a velocity of 3.0 m/s as shown in the diagram. Determine the maximum amount of the spring compresses if it spring constant is 335 N/m.

    For this one I don't know whether I should use E_kin = E_spring then solve from there or E_kin(i) + E_spring(i) = E_kin(f) + E_spring(f), but as for the former I got:

    1/2 mv^2 = 1/2 k (delta) l^2
    mv^2 = k(delta) l^2
    (3)(3)^2 = (335) (l^2)
    x = .081 m

    Is that right? Thanks a lot for your help so far, everyone! I really appreciate your time and kindness. :smile:
  2. jcsd
  3. Nov 20, 2005 #2
    looks good.

    except the spring epe is .5kx^2
  4. Nov 20, 2005 #3


    User Avatar
    Homework Helper
    Gold Member

    Both the equations are valid. The second one reduces to the first one since E_spring(i) is zero and E_kin(f) is zero.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook