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!

Quick Question on mass/spring system

  1. Jul 9, 2008 #1
    1. The problem statement, all variables and given/known data

    A 3Kg mass, attached to spring oscillates w/ amplitude of .15m and a period of 2s. At time t= 0.5s the objects position is .019m.

    Find the total energy of the system



    2. Relevant equations

    (.5)mv^2+(.5)kx^2= (.5)kA^2



    3. The attempt at a solution

    I found the spring constant to be 29.6 N/m... my only question is this... (.5)mv^2+(.5)kx^2
    would give me the answer, as would (.5)kA^2 correct? to get the total energy i just did (.5)(29.6)(.15)^2 = .333J

    Is that correct???
     
  2. jcsd
  3. Jul 9, 2008 #2

    rock.freak667

    User Avatar
    Homework Helper

    Yes it is.
     
  4. Jul 9, 2008 #3
    Thank a bunch rock... i also had one other quick question that i figure ill post here so i dont start another post minutes after this one...

    A periodic wave has the equation .15m*sin(10t+(pi)x)

    Now i am getting a little bit mixed up about how to determine the direction of the wave... Im going to say this wave is moving in a positive direction because (pi)x is positive... meaning it is going forward... is that correct? So when i rewrite the equation it would be .15m*sin(10t+(pi)(x-vt)) to account for the positive change? Thanks for all of the help guys.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?