どれくらい高速回転したらAirPodsは耳から外れるか【物理エンジン】

Cordless earbuds are convenient.

When earbuds get caught on something,

they'll come flying out of your ears, but

otherwise, they usually stay in your ears well enough.

Even doing a spin is totally fine

But if you keep spinning faster and faster...

Eventually, your centrifugal force
should be able to pull out your earbuds.

So how fast would you have to spin
for your earbuds to fall out?

Centrifugal force is determined by mrω²

m = mass of an earbud
r = radius (earbud's distance from the axis)
ω = angular velocity

First, measure the force required to remove the earbuds.

I used this spring scale to measure it.

Make sure that your earbuds'
tip covers are on correctly

Pull straight

It took 0.73 newtons to remove the earbud.
(plus or minus 0.007)

So if we take one 5.4g earbud

and gradually increase its weight...

it should separate when it goes above 74g,
which is about the weight of a large egg.

Now, let's make the person wearing these earbuds spin at high speed.

Keep in mind, the axis of rotation is the
point directly between both earbuds.

I made it a fixed axis so it won't wobble
no matter how fast he goes.

I'm going to gradually increase
the rotations per second.

The earbuds fell out after passing 6.5 rotations per second.

At the point of exit, the earbuds were being
subjected to 13.8 Gs of force.

Let's put this speed into perspective.

Looking up the figure skater records for jumps,

even Yuzuru Hanyu, who is going for the quadruple Axel,
is said to have 5.71 revolutions per second.

So even a Hanyu-level spin,
which you're looking at now,

it's safe to say your earbuds
probably won't come out.

On the other hand, the glasses (20g)...

started to shift at about 0.6N.

Earphones fall out > Hanyu spin > Glasses slip off

So, since spinning almost definitely won't
make your earbuds come out,

all you have to worry about is them
getting caught on something.