Now.

Normally, we neglect these effects.

When I'm teaching students about projectiles, I tell them, Forget about the air.

Let's just talk about gravity.

Could it simplifies the problem?

But it is Rael.

It's heavy stuff, and that affects the flight of old projectiles.

All right, well, why don't we do a little experiment to show the effect that air can have?

This is a surprising experience that we've set up here.

Festival show you what happens to a tennis ball when it rolls down this inclined ramp that falls exactly like I would expect, basically a parabolic path as predicted.

But let's try something a little bit light of, such as these paper cylinder Okay, waves only a gram or so the effect of the air will be more important.

Watch what happens.

It's time.

So the paper cylinder goes backwards.

That doesn't make any sense.

It was rolling forwards off that round.

Now it does it every time, and it's because of an effect known as the Magnus Force that's acting on spinning cylinder acts on spinning ball as well on people who play sports know about it.

But I wouldn't call it a Magnus.

Why is it called the Magnus Force?

Because Magnus was the first guy who discovered it when he was investigating why cannonballs curves like propagate through the air, huh?

And so what did he find out?

What he found us that went up a ball or any object you're spinning like this.

There's a force perpendicular to the spin axis.

If it's spinning clockwise or with top, spin the forces down.

If it's spinning anti clockwise, counter clockwise, the forces up.

So how do we get a Magnus force on the ball as the ball's moving forward through the air?

If it's spitting, the air is flying around the ball from the front to the back.

The ball is spinning in the same direction is the air flow at the top of the ball, but in the opposite direction at the bottom because of friction between the air in the ball, surface is dragged around the top of the ball downwards towards the back, but at the bottom of the ball, the air flower in the bar opposite directions.

The air comes to a screeching heart fairly soon.

Instead of being deflected upwards, the net result is air is deflected downwards.

Do you know Newton's third law?

The air exerts an equal opposite force on the ball, which is upwards.

So how would sports players take advantage of the Magnus Force?

They make the ball curve through the air by different amount than not due to gravity alone.

So a golf it will strike a golf ball with backspin that exerts a vertical force, our lift force on the ball that keeps it in the air for a longer time and therefore it travels further.

A tennis player will hit the ball with top spin that courses the ball to curve down onto the court after passions.

The net ah, baseball or cricket player will also do that.

But in addition, I can make a bowl cover about a vertical axis, in which case the ball will either curve to the left or to the right away from the battle, making it much more difficult to hit the ball.

That's the object of the exercise.

I see.

So are there any other air effects that we need to be aware of There's quite a few, Actually, there's the buoyant force acting on a balloon, for example, or any object that's a drag force acting backwards that slows the ball down.

And if the ball happens, tohave seems.

Then there's aside for sexting on the boat.

Uh huh.

Well, that sounds like a whole nother episode.

Balls with seems Yeah.

All right, well, stay tuned.

If you wanna find out how air effects bowls with seams, you really warm.