An Interesting Physics Problem

[_brady_]

[ QUOTE ]
Neither of those two answers appear to be correct.

Perhaps if you provided a worked out solution.

Edit: Ah, never mind. I see how you got that.

Definitely not.


[/ QUOTE ]

Ya, the first one I was sure was wrong and I just realized I did the second one wrong, so here is a reworked solution.

x direction parallel to slope, y direction perpendicular, angle is theta

Sum moments bout point of contact, P:

mgrsin(theta)=Ip*alpha

Ip=2/5mr²+mr²

d²x/dt² = a_x = r/2*alpha

solveing for acceleartion in x direction a_x

a_x = (5/14)*g*sin(theta)

Now summing forces in x direction:

-Ff + mgsin(theta) = m*a_x = m*(5/14)*g*sin(theta)

where Ff = mu*N = 0.5*N = 0.5mg*cos(theta)

-0.5mgcos(theta)+mgsin(theta)=5/14*mg*sin(theta)

solving for theta:

theta = 37.9 degrees from the horizontal.