How Ski Jumpers Can Land Safely at the Winter Olympics

If you jump off a building

and you land on the ground, it's not gonna be a good thing.

We can calculate the force

that the ground exerts on you during impact

by using the momentum principle.

This says that the total force on an object

is the rate of change in momentum,

where momentum is the product of mass and velocity.

So if you jump off, you're moving to some momentum down,

and then you stop, so you have zero momentum.

So your change in momentum can be kinda large and bad

if you have a large force.

In the ski jump, we have something similar

in that humans are going down very large distances,

but they don't have as much trouble on impact

because of one simple trick.

They still have a change in momentum

and they still have a force exerted on them.

So we still have the momentum principle.

But the key is that the landing slope is angled,

so they're moving down at some angle like this.

That's a vector.

That's their initial momentum.

Their final momentum is this direction.

So yes, there is a change in momentum,

but it's very small because you're still moving

in that direction.

They don't just stop.

This means that the impact force

is gonna also be very small, unless they crash.

Don't crash.