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Mechanical Properties Of Fluids

Question
CBSEENPH11018115

Two wires of diameter 0.25 cm, one made of steel and the other made of brass are loaded as shown in Fig. 9.13. The unloaded length of steel wire is 1.5 m and that of brass wire is 1.0 m. Compute the elongations of the steel and the brass wires.

Solution

Given, 
Diameter of the wires = 0.25 cm
That is, d= d= 0.25 cm

Therefore, 
Radius of the wires will be given by, 

rs = rB = 0.125  cm = 1.25 ×10-4 m

Unloaded length of the steel wire, Ls=1.5 m
Unloaded length of the brass wire, L= 1 m

Young's modulus of steel, Ys = 2 × 1011 Pa
Young's modulus of brass, YB0.91 × 1011 Pa
m1 = 4 kg and m2 = 6 kg

Brass wire is under a tension of load 6 kg.

Therefore, increase in length is given by

Ls = FAsLBYB= 6×9.8×10π (1.25×10-4)2 × 0.91×1011 m 
Since, brass wire is under a tension of load 6 kg.

"
Steel wire is under a tension of 10 kg load. 

Therefore, elongation of length of the wire, 

 LS = FAsLsYs               = 10×9.8×1.5π (1.25×10-4)2 × 1011m               = 1.5 × 10-4 m