A uniform rectangle sign h=20.0cm high and w=11.0cm wide loses three of its four support bolts(at points p_1, P_3, and p_4) and rotates into the position as shown, with p_1 directly over p_3. It is supported by the bolt P_2, which is so tight it holds the sign from further rotation. Find the gravitational torque about p_2, if the mass of the sign is 5.0kg.
I couldn't get my image to appear but here is what is looks like: http://www.cramster.com/answers-apr-10/physics/physics-1-uniform-rectangular-sign-16-cm-high-andw-16-cm-wide_816165.aspx?rec=0
I am not really sure where to even begin on this problem so any input would be great! Thanks