Re: Problem with a problem

[Science Lab1 <emigh@COMMNET.EDU>]

Timely problem, I will use it in class next Monday.

First of all make sure that you use angular terms throughout, so
velocity squared over radius is written as radius times angular velocity
squared.  When you do this you know that the tangent of 60 degrees has
to be tangential acceleration over centripital acceleration.  The r's
cancel so you can calculate alpha.  Once you have alpha you can go back
to the magnitude equation and solve for r.

David

"Harry L. Hightower" wrote:

>         How do you go about solving the following problem?
>         A thin rigid rod is rotating with a constant angular
> acceleration about an axis that passes perpendicularly
> through one of its ends. At one instant, the total
> acceleration vector (centripetal plus tangential) at the
> other end of the rod makes a 60.0 degree angle with
> respect to the rod and has a magnitude of 15.0 m/s/s.
> The rod has an angular speed of 2.00 rad/s at this
> instant. What is the rod's length?
>         I am probably making this harder than what it really is.
>
>                                            Thanks
>                                                    Harry