An initially stress-free massless elastic beam of length L and circular cross-section with diameter d (d ≪ L) is held fixed between two walls as shown. The beam material has Young’s modulus E and coefficient of thermal expansion α. If the beam is slowly and uniformly heated, the temperature rise required to cause the beam to buckle is proportional to

An initially stress-free massless elastic beam of length L and circula

1.	An initially stress-free massless elastic beam of length L and circular cross-section with diameter d (d ≪ L) is held fixed between two walls as shown. The beam material has Young’s modulus E and coefficient of thermal expansion α. If the beam is slowly and uniformly heated, the temperature rise required to cause the beam to buckle is proportional to
A.	d
B.	d2
C.	d3
D.	d4
Answer» C. d3