(adsbygoogle = window.adsbygoogle || []).push({}); HELP!!!a question on angular velocity

1. The problem statement, all variables and given/known data

A horizontal cylindrical rod is free to rotate about a vertical axis perpendicular to its length through its centre of mass. two beads of mass m and 2m are each a distance l from the axis of rotation and are tied together by a light string. the coefficient of static friction between each of the beads and the rod is mu(s). the rod accelerates from rest with a constant angular acceleration alpha. find the angular velocity of the rod at the instant the beads start to move along the rod, if mu(s)=1/12, l=2.0m (radius), and alpha=1.5rad/s

2. Relevant equations

centripetal or radial acceleration:

LaTeX Code: <BR>a_c = \\frac{v^2}{r} = r\\omega^2<BR>

tangential acceleration:

LaTeX Code: <BR>a_{\\rm tan} = r\\alpha<BR>

3. The attempt at a solution

first of all, I tried to find tangential acceleration:

a=radius*alpha

=2.0*1.5

=3m/s^2

than I have to solve for the centripetal acceleration:

a=v^2/r=r*omega^2

two unknown variables, so we have to solve for a

Frictional force=mu(s)*m*g

mu(s)=1/12 g=9.8

and

frictional force=ma

mu(s)*m*g=ma

a=1/12*9.8=0.8167

then omega=0.639

I am wondering, for this question which is the answer we want, omega or tangential accleration? or others?

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# Homework Help: HELP a question on angular velocity

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