Like if I threw an egg at a wall the egg would break, but if the egg is going really fast the wall would break too? Whats the underlying mechanic for this?
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The amount of force involved. The egg needs 1kN of force applied to the shell to break and the wall needs 100kN. Force from the impact is proportional to the speed you throw at and the mass of the thrown object.
Edit: after the egg shatters the force it exerts on the wall quickly drops because it isn’t a single solid object anymore, so the calculations get a bit harder than just speed and mass. But that’s the general idea.
(All the values just estimated without any calculations, actual numbers are probably very different).
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Given that in an impact both objects experience the same force, what decides which object breaks is the hardness of the material. Softer materials, ergo, the egg, will break when hitting stronger surfaces. Obviously, the force of impact adds to it, but very little.
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F=ma. Force = Mass x acceleration. You can make a lot of force with a small amount of mass by increasing the acceleration by a lot, granted the lighter something is the harder it is to actually throw it hard but it’s not impossible. But this is why a relatively soft bullet can damage a much stronger piece of metal.
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When two objects collide, the force of the collision is distributed through the items colliding according to the shapes and materials of those items. If the force is too great for the weakest point in either item then that point will fail and the relevant item will undergo consequent changes such as deformation, fragmentation and so on.
According to Newton’s Law’s of Motion, technically the egg and the wall apply the same amount of force on each other. To put simply, the deciding factor is usually mass.
Think of it like this, if two marbles were to roll towards each other at the exact same speed, but one marble was heavier then the other, the momentum will shift so that the heavier marble will continue on it’s course.
This same sort of example is applied here, except at a more extreme scale.
The answers you’re getting are misleading or at the very least they are incomplete. In any impact/collision the same force is applied to both objects. What breaks an object isn’t force, it’s stress. Any object who’s stress at a certain location exceeds its limit would break. It can be either object, it can be both objects or it can be none of the objects. In the case of an egg, the shell is very thing and brittle meaning it is easier to break than a typical wall, but make the wall thin enough or out of a material that is weak enough and you could easily punch a hole in the wall using an egg.
Metaphor time:
Let’s remove everything you know to make it really obvious.
I have a flat pool table (With raised sides).
This table is full of holes rather then the normal 6, think sieve.
The odd holes have a shallow cup below.
The even holes have a deep cup below.
I pour a bucket of water in the middle of the table.
Some cups will fill regardless of their depths but more shallow cups will be filled to the brim than deep ones, especially when you get away from where I poured.
The more water I pour the more likely it is that a lot of deep cups will be full no matter what I do.
The water is the kinetic energy of whatever you are throwing.
The hardness, elasticity, heat, crystal structure, etc… determines the depth of the cups for each materials but you can simplify it for ELI5 to how hard an object is determines how deep the cup is.
No matter what the Kinetic energy is spread to both items evenly.
What determines the break is how many cups get filled.
something like an egg has very very shallow cups so any amount of water will fill some and cause a break.
A wall on the other hand has reasonably deep cups so it will take some water to fill even one cup.
However if you pour enough water it doesn’t matter what the small cups are the big cups will get filled too.
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