Phycis Help

[fatema]

if we have brick and we compress it it cannot break but where we stretch it, it breaks why?

[chiaroscuro]

When you compress you are pushing molecules together, when you strtech you are pulling them apart.

[EDDIE51]

A brick will crush to rubble if you compress it hard enough . It will break if you pull it apart as it is brittle rather than elastic.( imagine a brick made of rubber)
I used to crush bricks and concrete every day to test their strength.

[EDDIE51]

Here is a video of a brick being compressed until it breaks to test it's strength

I used to do this test every day to check the strength of brick / concrete used in a mine to support the roof.

[New Judge]

Some materials are resistant to compression but weaker in tension (concrete, for example). Some are the other way round (e.g. cast iron).

[Karolina82]

A brick is full of voids. When it is put into tension, the stress concentrates at the edge of the voids, especially if the angle is small. This causes cracks which then readily propagate. By their very nature, cracks present a small angle to the tension force and which results in a high stress concentration.