Tension is a force that tends to stretch a material, as shown in Figure 1.1. For example,
(i) the rope or cable of a crane carrying a load is in tension
(ii) rubber bands, when stretched, are in tension
(iii) when a nut is tightened, a bolt is under tension
A tensile force, i.e. one producing tension, increases the length of the material on which it acts.
