Mechanical Engineering - Strength of Materials - Discussion
Discussion Forum : Strength of Materials - Section 1 (Q.No. 34)
34.
When a bar is cooled to - 5°C, it will develop
Discussion:
105 comments Page 3 of 11.
Agoda isaac said:
1 decade ago
A bar is compressive when cooling because when cooling it is contrasting and as we know compression forces are forces that act inwardly in a body while expansion is tensile force because it is elongating the bar that is, the forces acting away from the bar.
Baap said:
1 decade ago
No stress will induce, because no restriction in contracting the bar.
Akshay said:
1 decade ago
Stress = internal resistance therefore when the bar is cooled it just shrinks, there is no internal resistance offered by the body until and unless the bar is constrained to shrink by holding it at both ends. Hence answer should be no stress.
Swapna said:
1 decade ago
Stress will not depend on the temperature. So no stress.
Ashok said:
1 decade ago
Bar means tensile loaded mechanical element if it cools tensile stress are developed(imagine).
Rao said:
1 decade ago
Compressive stress is are induced in body of material only, but that is fixed at both ends then, that create tensile stress at ends, if beam is not fixed at ends there no stress developed.
Praveeen V said:
1 decade ago
Compressive stress is induced because when cooling the material will contract, hence there is resistance by the molecules of the material.
Aman said:
1 decade ago
Correct answer is tensile stress b/c bar material resist the force which want to do the shrink the material.
Ravi said:
1 decade ago
Compressive stress is the answer (strain is a reacting force to stress, hence the strain is tensile). As far as option a is considered, stress relieving starts at 450 degrees C. Simply because metals expand on heating and contract on cooling direct effect of which will be considered stress!
Hemant mishra said:
1 decade ago
Tensile stress is right answer. When bar cooled it molecules shrinks so they will try to expand due to resistance tensile force.
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