Why Do Speed Skaters at the Winter Olympics Lean So Much?

Why do speed skaters on the short track lean so much?

The first thing that you need to know is that,

if you are moving in a circle,

even at a constant speed, you accelerate.

So the definition of acceleration is the change in velocity.

But if you change direction, that is a change in velocity,

that is an acceleration.

The direction of that acceleration

is towards the center of the circle,

this is the circle of radius R,

and the magnitude of acceleration is the velocity squared,

divided by the radius of the circle that you're moving it.

And we call that centripetal acceleration,

center-pointing acceleration,

'cause it points toward the center of the circle.

Now, imagine that you're going around a circle,

but you're standing up straight right here.

Well, we have really two forces acting on the person,

but we can add a third fake force.

So we can envision this acceleration

as a force in the opposite direction.

In this case, that fake force, it's a fake force,

it'd be pushing away from the circle.

So we call that centrifugal force

'cause it's center-fleeing.

In this situation, imagine a stick like this,

with that force pushing that way,

at the center of mass.

It's gonna tip you over. You're gonna fall over.

If you try to go around in a circle standing up straight,

you're gonna fall over.

You can counteract that by leaning into the turn.

Now I have the ice pushing up,

gravity pulls down, and the fake force pushes this way.

The torque due to these two things equal and cancel,

and you are in a stable position.

So you have to lean over in order to not fall over

because you're accelerating

towards the center of the circle.