State the two conditions that must be satisfied for a body to be in equilibrium.
Three co-planar forces act on a body that is in equilibrium.
Describe how to draw a vector triangle to represent these forces
State how the triangle confirms that the forces are in equilibrium.
A weight of 
hangs vertically by two strings AB and AC, as shown in the figure below
For the weight to be in equilibrium, the tension in string AB is 
and in string AC it is 
. On the above figure, draw a vector triangle to determine the magnitudes of and .
By reference to the figure, suggest why the weight could not be supported with the strings AB and AC both horizontal.
and 
respectively.
