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: Need help setting up basic dynamics problem

  1. Sep 13, 2005 #1
    http://fletchowns.net/incoming/picture.jpg [Broken]

    point a oscillates with accel of a=2880-144x. Magnitude of velocity is 11in/s when x=20.4in. Determine the max velocity of A & two positions at which velocity is zero.

    Why am I getting this wrong :( It seems so easy

    integrate a=2880-144x to get v, plug in 11in/s and 20.4in as the initial values, solve for the constant and you get the velocity equation. From the acceleration equation you know there is a critical value at x=20in, so plugging x=20 to the velocity equation should give you the max velocity, and the other part is just finding the zeroes of v=...is that the right setup?
    Last edited by a moderator: May 2, 2017
  2. jcsd
  3. Sep 13, 2005 #2


    User Avatar
    Homework Helper

    Your initial value (v=11in/s) is NOT QUITE at maximum-velocity
    location, so if you did not include a phase angle or time-offset,
    (ending up with 20.917...) that might be your error.

    umm, how do you know you're getting it wrong?
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook