Need help setting up basic dynamics problem

[fletch]

http://fletchowns.net/incoming/picture.jpg

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?

 

[lightgrav]

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?