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: Simple Harmonic Motion - Acceleration

  1. Jun 28, 2011 #1
    Hi, :smile:

    Assuming that the motion of the hydrogen atom is simple harmonic, its frequency of oscillation, f, is given by the expression:

    f = 1 / 2π * √(k/m)​

    where k is the force per unit displacement between a hydrogen atom and the carbon atom and the m is the mass of a proton.

    (i) Show that the value of k is approximately 560 N/m
    (From previous parts of this question I knew: f = 9.1 x 1013 Hz and the mass was 1.7 x 10-27

    I managed to do this question by rearranging and plugging the numbers in the formula

    However, I am having problems with part (ii)

    (ii) Estimate, using your answers to (c)(i), the maximum acceleration of the hydrogen atom.

    I am thinking either F = ma, where F = kx. In this case, the k I got from the previous question would be the constant k, or the F itself?

    Or use a = -ω2x, using the maximum displacement (I have it from previous part of the question)

    How should I approach the second part with the F = ma format? Is it possible to tackle the problem in those two ways?

    Peter G.
  2. jcsd
  3. Jun 28, 2011 #2

    Doc Al

    User Avatar

    Staff: Mentor

    That method would work, but I don't understand the question. (Of course the k will be the constant k.)

    That works.

    What's the maximum force?
  4. Jun 28, 2011 #3
    The maximum force would be the constant multiplied by the maximum displacement?
  5. Jun 28, 2011 #4

    Doc Al

    User Avatar

    Staff: Mentor

    Exactly. Now you can use Newton's 2nd law to calculate the maximum acceleration.

    (Be sure to solve it both ways--convince yourself that the methods are equivalent.)
  6. Jun 28, 2011 #5
    Ok, will do!

Share this great discussion with others via Reddit, Google+, Twitter, or Facebook