For example, I’ve seen that an electron is assumed to be a point-particle, i.e, occupies negligible space.
But it obviously has mass, so it’s gotta occupy *some* space!
However, the math seems to add up (pun intended), and the behaviour of the electron can be explained.
How?
(This was inspired by the *assume a spherical cow* thing)
In: Physics
Assumptions for physics depend on the problem you’re solving
If you’re working on electronics then its fine to assume an electron is a point particle, the size of the electron doesn’t have an impact on your work
If you’re designing a new type of electron microscope then you can’t make simplified assumptions about the electron because all their quirky properties have significant impacts on what you’re working on.
Most of the math you’ll do in physics or engineering classes makes a boatload of assumptions because it gives you a good enough answer.
If you’re just solving projectile motion for a heavy cannonball fired at 20 degrees at a fairly slow speed then air resistance doesn’t particularly matter and we ignore it to make life easier. If you’re making actual artillery firing tables in advance then you’ll need to factor in air resistance and the shape of the shell. If you’re calculating a real time firing solution and you want to hit *that* pillbox, then you can’t just use 1.225 for air density, you need to factor in altitude(which changes over flight), temperature, and humidity to get an accurate firing solution.
The level of assumptions you can make is entirely dependent upon the level of detail required for the application. For most things you can assume gravity is 9.8 and pi is 3.1 and end up just a couple percent off the answer and its fine because most applications have margins of safety built in to accept the unknowns of the real world.
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