problem

[shogo]

hi, this problem is really driving me mad
take a look at here: Link (http://tokplatsen.ath.cx/phy.html)

I don't know what formulas to work with,

shogo

[gnome]

what formulas?

F=ma
f=μN
cos=adj/hyp
[6)] [6)]

All kidding aside, here's a clue to get you started:

Realize that the friction between the arms and the pyramid acts parallel to the sides of the pyramid. You have to figure out the vertical and horizontal components of the friction and the the vertical & horizontal components of the pressure from the crane.

Now ask yourself, what relationship between the friction and the pressure (ignore gravity for the moment) is necessary for the crane to be able to hold the pyramid?

[shogo]

I've gotten to something like:
sin a = μmg/(2f)

where f is "F-friction", but now I'm stuck..
Can anyone show me how to solve it all the way?