# Hole in an aluminium plate and that plate is heated

#### Inderjeet Singh1208

Homework Statement
THere i a hole in an aluminum plate.What will happen to the hole if we increase the temperature by 100K. THe initial temp. was 300K
Homework Equations
delta L= $*deltaT , where L=length, delta = change,$= coefficient of linear expansion and T is the temperature.
the radius of the hole should decrease from my perspective but the book says that the radius of the hole will increase. I am not able to understand why??

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#### Orodruin

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Why do you think the hole should decrease?

#### kuruman

Homework Helper
Gold Member
Take an aluminum plate and cut a circular disk out of it. Place the plate and the disk side by side on a hot plate and turn it on to "High". In view of what you know about thermal expansion, which of the following makes more sense to you?

1. You will be able to put the disk back in the hole and take it out again at any temperature as both the hole and the disk contract together.
2. You will be able to put the disk back in the hole and take it out again at any temperature as both the hole and the disk expand together.
3. You will not be able to put the disk back in the hole because the disk will expand and the hole will contract.
4. You will be able to put the disk loosely in the hole because the disk will contract and the hole will expand.
5. Other (please explain) ______________________________ .

Note: Assume that you used an infinitely thin saw to make the cut. This is a thought experiment.

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"Hole in an aluminium plate and that plate is heated"

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