Question

An aluminum bullet is in a hole in an aluminum plate that is too small until it falls through. Both the plate and the ball heat up as much. Will the ball fall through?what if the ball was made of steel? explain your answers

Answer 1

In first case when both the bullet and plate made from aluminium, the ball will not fall through as both the bullet and plate expand with same rate (thermal expansion coefficient for both is same) .

Now in another case when ball made up of steel and plate is still made from Aluminium then ball will fall through as thermal expansion coefficient is high for aluminium and low for steel so plate will expand faster than ball and so that ball will fall through.

I am attaching a picture in which thermal expansion coefficient of different metals are given.

Attached picture source- Google