Mechanical Properties of Solids
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Question : 5
Total: 21
Two wires of diameter 0.25 cm, one made of steel andthe other made of brass are loaded as shown in figure. Theunloaded length of steel wire is 1.5 m and that of brass wireis 1.0 m. Compute the elongations of the steel and the brasswires.
Solution:
For steel wire : total force on steel wire:
F 1 = 4 + 6 = 10 k g ,
f = 10 × 9.8 N ,
l 1 = 1.5 m , Δ l 1 = ? ;
2 r 1 = 0.25 c m
orr 1 = (
) c m = 0.125 × 10 − 2 m ,
Y 1 = 2.0 × 10 11 P a
For brass wire,F 2 = 6.0 k g ,
f = 6 × 9.8 N , 2 r 2 = 0.25 c m
orr 2 = (
) c m = 0.125 × 10 − 2 m ;
Y 2 = 0.91 × 10 11 P a , l 2 = 1.0 m ,
Δ l 2 = ?
As,Y 1 =
=
orΔ l 1 =
=
= 1.49 × 10 − 4 m
AndΔ l 2 =
− =
= 1.3 × 10 − 4 m
or
For brass wire,
or
As,
or
And
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