Properties Of Solids And Liquids Question 555

Question: When a building is constructed at 10C , a steel beam (cross-sectional area 45cm2 ) is put in place with its ends cemented in pillars. If the sealed ends cannot move, what will be the compressional force in the beam when the temperature is 25C ? For this kind of steel, α=1.1×105oC1 and Y=2.0×1011N/m2 .

Options:

A) 2.5×103N

B) 3.5×105N

C) 2.5×105N

D) 3.5×103N

Show Answer

Answer:

Correct Answer: B

Solution:

ΔLL0=αΔT=(1.1×105oC1)(35oC)

[ΔL=L0αΔT] where, ΔL= Change in length and L0= original length =3.85×104 So, F=YAΔLL0

[Young  smodulus,Y=F/AΔL/L0]

=(2.0×1011N/m2)

(45×104m2)(3.85×104)

=3.5×105N



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