physic
posted by help me please .
A steel rod of length 1.0000 m and crosssectional area 3.63·104m2 is placed snugly against two immobile end points. The rod is initially placed when the temperature is 0°C. Find the stress in the rod when the temperature rises to 38.9°C.

Thermal expansion equals stress compression. Solve for the stress, sigma.
L*(alpha)*(delta T) = (sigma/E)*L
sigma = E*(alpha)*(deltaT)
E is Young's modulus for steel
delta T = 38.9 C
alpha is the linear coefficient of thermal expansionm of styel
L cancels out and is not needed.