Temperature and Kinetic Theory

[pupatel]

An aluminum bar has the precisely desired length when at 15°C. How much stress is required to keep it at this length if the temperature increases to
35°C?

How do I do this????? can anyone help me please.... :yuck:

[Doc Al]

If no stress were applied, how much would the bar expand? (You'll need to understand the coefficient of thermal expansion.)

Then consider how much pressure needs to be applied to compress the bar back to its original length. (You'll need to understand Young's modulus.)