Question

A light rod of length 200 cm is suspended from the ceiling horizontally by means of two vertical wires of equal length tied to its ends. One of the wires is made of steel and is of crosssectional area 0.1 cm² and the other is of brass of crosssectional area 0.2 cm² . Find out the position along the rod at which weights may be hung to produce 

(a) equal stress in both wires 

(b) equal strains in both wires. Ysteel = 20 x 10¹¹ dynes/cm² and YBrass = 10 x 10¹¹ dynes/cm² .

Answer 1

(a) Let a weight W be suspended from a point C on the rod such that it is x cm from the steel wire. Let the forces in steel & brass wires be F₁ and F₂ respectively. 

(b) Let the weight w be hung at a point y cm away from the steel wire and forces developed in the steel & brass wires be F₃ and F₄ respectively