Rotational Kinematics-Bead Constrained in a Hoop Rotating

[Darkalyan]

Homework Statement

http://docs.google.com/Doc?id=d277r7r_58d3chgqfj

Homework Equations

a=w^2*r

The Attempt at a Solution

a=w^2*r
w^2*r*cos(theta)=-mg

theta=arcos(-mg/(Rw^2))

I'm pretty sure that's right, because the vertical component of the acceleration has to equal the vertical component due to gravity. However, I wasn't sure if acceleration was simply w^2*R or if I had to do something more complicated to find it. Is my reasoning/answer correct?

 

[ak1948]

That's pretty close. You can see it's not quite right, though, because your second equation in your attempt at a solution part is dimensionally inconsistant. You have a force equal to an acceleration.

 

[Darkalyan]

oooh. didn't catch that. thank you. so then i just add a m to the left side of the equation, which makes the m's cancel out, and the final answer is theta=arcos(-g/(Rw^2)) Is that right now?