A heavy uniform rod hangs vertically from a fixed support and stretches under its own weight. How does its diameter vary along its length?

smallest at the top and gradually increases down the rod
largest at the top and gradually decreases down the rod
uniform every where
maximum in the middle.

Correct answer: smallest at the top and gradually increases down the rod

Solution

The top supports the entire weight below it, so stress and stretching are maximum there, making the diameter smallest at the top and larger toward the bottom.

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