sugary jelly-filled donuts, and then there are the ones that

are really bad for your health.

These ones.

Well, I can see why people pay money to watch this.

But take any friction fighting hijinks to the roads

and it's a serious hazard for motorists and for trees.

They were okay, but extremely lucky.

So you should never attempt this.

But off the road, and in the hands of an expert,

donuts are a masterclass in static and kinetic friction.

Our driver hits the gas hard and turns sharply.

The excessive torque at the rear wheels

overcome static friction between the tires and the ground,

so they become subject to kinetic friction,

which offers less resistance.

The reduced grip allows centrifugal force

to slide the wheels in a circular path,

like the ring of a donut.

So not just risky, but scientifically

tricky to pull off, although not everyone seems to think so.

I mean this guy thinks he's got the science down,

but in fact he hasn't lost traction at his back tires

at all.

He's just using rollers, see, which does reduce the risk

of kinetic friction, burning up the tires,

but doesn't make it less dangerous.

CAMERA MAN: Woah!

Watch out, man!

BEN AARON: It's a bit late for that.

Ah, the parking lot donut, using kinetic friction

and centrifugal force to drift into a space, like a glove.

Having successfully turned static friction

to kinetic at the rear wheels, he then

momentarily let up the power on those wheels

and went back to static.

So, he stopped circling, and went straight.

There are better ways to park a car.