UPSC Civil Service Exam Questions - Engineering

Q1:

A steel bar of 2 m length is fixed at both ends at 20°C. The coefficient of thermal expansion is 11 x 10-6/°C and the modulus of the elasticity is 2 x 106 kg/cm2. If the temperature is changed to 18°C, then the bar will be experience a stress of

A 22 kg/cm2 (tensile)

B 22 kg/cm2 (compressive)

C 44 kg/cm2 (compressive)

D 44 kg/cm2 (tensile)

ANS:C - 44 kg/cm2 (compressive)

Option D is correct.

Compression in the free bar but, due to fixed conditions it will experience opposite stress which is tensile.