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!

Find position after t for simple harmonic motion

  1. Jun 9, 2009 #1
    A 28.0 kg block at rest on a horizontal frictionless air track is connected to the wall via a spring. The equilibrium position of the mass is defined to be at x=0. Somebody pushes the mass to the position x= 0.350 m, then lets go. The mass undergoes simple harmonic motion with a period of 4.70 s. What is the position of the mass 3.854 s after the mass is released?

    T=2pi*sqrt m/k
    KE1+PE1=KE2+PE2 from this you get mv^2=KA^2
    x=Asin *omega*t
    omega=2pi*frequency
    frequency =1/T

    I used the first equation get k=3.92
    then I use that k in the second equation, but I dont know how to get v to then get A. Any help? Would I then take that A and plug it into the third equation to get my X?
     
  2. jcsd
  3. Jun 10, 2009 #2

    rl.bhat

    User Avatar
    Homework Helper

    In the given problem the amplitude A is given. ( 0.35 m). Find x.
     
  4. Jun 10, 2009 #3
    So I plugged in A (.35m) into the equation,
    x=.35sin(1.34*3.854) and got x=.032 which is still incorrect? Any help on where I am going wrong?
    The second part of this problem calls for the maximum acceleration- would I use the equation a=omega^2cos omega *t? I don't think that I will get this problem correct if I got the last one incorrect.
     
  5. Jun 10, 2009 #4
    Your formula for posistion does not work at t=0! You need a phase angle in it, or use cosine instead of sine.
     
  6. Jun 10, 2009 #5
    I figured this problem out. Thank you!
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Find position after t for simple harmonic motion
Loading...