Statics:
A metal homogeneous opaque ball with radius r was fastened from a point on its surface with a robe and the other end was fastened on point (A) on a rough vertical wall, the ball stationed in balance and It was about to slip down the wall at point (B). If AB = sqrt(3) r and the friction coefficient between the ball and wall is 1/sqrt(3).Prove that the tan of the angle which the robe makes with the wall is sqrt(3)/2 notice that the the action line of the ball weight affects on it's center.

Question

Statics:
A metal homogeneous opaque ball with radius r  was fastened from a point on its surface with a robe and the other end was fastened on point (A) on a rough vertical wall, the ball stationed in balance and It was about to slip down the wall at point (B). If AB = sqrt(3) r  and the friction coefficient  between the ball and wall is 1/sqrt(3).Prove that the tan of the angle which the robe makes with the wall is sqrt(3)/2 notice that the the action line of the ball weight affects on it's  center.

dan815 · Answer

what is the form for rotational intertia

dan815 · Answer

you should have just drawn it :P

trojanpoem · Answer

I though you'd prefer to draw it yourself :D

trojanpoem · Answer

|dw:1435161429650:dw|

trojanpoem · Answer

I can't add the lengths or the drawing will be nasty.

dan815 · Answer

woah okay, this is confusing drawing

dan815 · Answer

where is the horizontal wall?

trojanpoem · Answer

Notice that :
Fg = weight of the ball
Fb = force of pulling in the robe
m  = friction coefficient
r    = reaction of the wall

trojanpoem · Answer

typo not horizontal but vertical.

dan815 · Answer

okay lemme try drawing it and see if i got this right

dan815 · Answer

|dw:1435161896312:dw|