(a)[2]
State the two conditions that must be satisfied if a body is to be in equilibrium.
(b(i))[3]
Three co-planar forces act on a body that is in equilibrium. Describe how you would draw a vector triangle to show these forces.
(b(ii))[1]
State how the triangle shows that the forces are in equilibrium.
(c)[3]
A weight of $7.0\,\text{N}$ hangs vertically from two strings AB and AC, as shown in Fig. 2.1. To keep the weight in equilibrium, the tension in string AB is $T_1$ and in string AC is $T_2$. On Fig. 2.1, draw a vector triangle to find the magnitudes of $T_1$ and $T_2$.
(d)[2]
By referring to Fig. 2.1, suggest why the weight could not be supported if strings AB and AC were both horizontal.