A horizontal steel railroad track has a length of 100 m when the temperature is 25C. The track is constrained from expanding or bending. The stress on the strack on a hot summer day, when the temperature is 40C, is (Note : the linear coefficient of thermal expansion for steel is 1.1 x 10–5 /C and the Young'* modulus of steel is 2 x 1011 Pa)
(A) 6.6 x 107 Pa
(B) 8.8 x 107 Pa
(C) 3.3 x 107 Pa
(D) 5.5 x 107 Pa
Correct option (C) 3.3 x 107 Pa
Explanation:
When some body is constrained from expanding or bending then on heating thermal stress get develop in the body.
Stress = Y αΔT =
2 × 1011 x 1.1 x 10–5 x (40 – 25)
= 3.3 × 107 N/m2
= 3.3 x 107 Pa
