ELI5- How exactly do mass and density differ in their contribution to an object’s ability to resist deformation?

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I know mass moreso helps specifically with how hard an object is to move around, but what about a massive object that is less dense than another but still has more mass overall, would it be harder to deform all else equal?

In: Physics

2 Answers

Anonymous 0 Comments

Mass and density are just heuristics that sometimes work for ability to resist deformation since a lot of low density stuff is filled with air.

But really they don’t directly have anything to do with it.

Butter is way denser than wood, depending on the wood by a factor of 10.

Anonymous 0 Comments

>all else being equal

If you used the same substance but made it denser, then it would be under extremely high pressures. It’s pretty much impossible to hold “all else equal”.

The way an object responds to slow deformation has nothing to do with its density, at least not directly, and the way it responds to *fast* deformation is almost exclusively related to density. This is because inertia – something that mass gives to an object – responds to rate of change. A fast impact is a sudden change, a slow impact is a very drawn out change.