I already got the answer for the case a
but at the case b, i don't know how to sum all of the torques.
I'm thinking of using integral, but i don't know where to put the pivot point for the torque.
I don't know how to search for the pivot point.
Can anybody give me hints so i could find the pivot...
So, if i make the angle between vertical axis and PC is y, and the equilibrium angle x
The net torques are
mg sin(x)(R cos(x+y)+R+L)-mg cos(x)(R sin(x+y)) =0
sin(x)(R+L) = R sin(y)
and from the forces
tan(y)=u
sin(y)=u/sqrt(1+u^2)
then i get
sin(x) = (Ru)/((R+L)sqrt(1+u^2))
Is that correct ?
Oh, so is it like
Mg cos(x)R-Mg sin(x)(R+L)=0
and tan(x) = R/(R+L)
Also, from the force equilibrium, i got
tan(x)=1/u
cos(x)=u/sqrt(1+u^2)
The answer from the book is
x=arcsin((Ru)/((R+L)sqrt(1+u^2))
I can get it if i multiply tan(x) from the torque with cos(x) from the force,
but why it...
-I tried to draw the forces on the hoop when it is in the equilibrium state. I know there are friction and normal force on the contact point of the shaft and the hoop
-I also put the weight force to the M object
-But when i used the torque equilibrium, where the pivot is the contact point of the...