- #1
songoku
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Homework Statement
A three-legged stool has one leg of aluminium (E = 7 x 1010 Pa), one copper (E = 11 x 1010 Pa) and one of steel (E = 20 x 1010) Pa. The legs have the same dimensions. If the load on the stool is at the exact center,
a. Which leg is under the greatest stress? Explain why
b. Which leg experience the greatest strain? Explain why
Homework Equations
stress = force / area
strain = extension / original length
young modulus = stress /strain
force = (E.A.extension) / original length
The Attempt at a Solution
a. All the legs have same dimensions means that the area are the same, so the stress is directly proportional to the force. Assuming they all have the same extension, then the force is directly proportional to young modulus. So the steel is under the greatest stress
b. Because all the legs have same extension and original length, the strain experienced is the same for all
Am I correct? I am really not sure, especially about the assumption that the extension is the same for all.
Thanks