1. Not finding help here? Sign up for a free 30min 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!

Two springs and the energy question

  1. Apr 9, 2012 #1
    1. The problem statement, all variables and given/known data

    A horizontal slingshot consists of two light, identical springs (with spring constants of 24.1 N/m) and a light cup that holds a 1.21-kg stone. Each spring has an equilibrium length of 50 cm. When the springs are in equilibrium, they line up vertically. Suppose that the cup containing the mass is pulled to x = 0.7 m to the left of the vertical and then released. Determine

    a) the system’s total mechanical energy.


    b) the speed of the stone at x = 0.




    2. Relevant equations



    3. The attempt at a solution
     

    Attached Files:

  2. jcsd
  3. Apr 9, 2012 #2

    tiny-tim

    User Avatar
    Science Advisor
    Homework Helper

    welcome to pf!

    hi coldpay! welcome to pf! :wink:

    show us what you've tried, and where you're stuck, and then we'll know how to help! :smile:
     
  4. Apr 10, 2012 #3
    i know the the total mechanical energy is mgh plus 0.5kx^2 but i can't find the answer.

    answers
    a)3.127 J
    b)2.274 m/s
     
  5. Apr 10, 2012 #4

    berkeman

    User Avatar

    Staff: Mentor

    I don't think the mgh term will change by pulling back the slingshot. Calculate how much energy is stored in the springs as they are pulled from their equilibrium postition back to the position shown. Show us your work please.
     
  6. Apr 10, 2012 #5
    X=√0.5^2+0.7^2=0.86

    0.5kx^2=0.5*48.2*(0.86)^2=17.34 i found this but i am not sure if the spring is parallel or serial(i take it parallel)

    This is all i can do.I dont know the rest of the question.
     
  7. Apr 10, 2012 #6

    berkeman

    User Avatar

    Staff: Mentor

    In the spring equation, the "X" is meant to be the amount of stretch, not the overall length.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Two springs and the energy question
  1. Spring energy question (Replies: 5)

Loading...