Question

A rubber rope of length 8 m is suspended from the ceiling of a room. Given

Y = 5 x 10⁶ NM^-2 for rubber; ρ = 1.5 x 10³ kg m^-3 ; g = 10 ms^-2. The elenogation in the rope due to its own weight is

(1) 96 mm

(2) 24 mm

(3) 48 mm

(4) 344 mm

Answer 1

(1) 96 mm

Mass of the rope = Volume x Density

M = AL.p

The weight of the rope will act at its centre of gravity. So for the purpose of calculation of elongation; the original length of the rope is L/2 Now