Kind: captions
Language: en
Now, I'd like you to make a prediction.
In my left hand, I have a basketball. In
my right hand, a 5 kg medicine ball. If
I hold them both above my head and then
let them go simultaneously,
which one will hit the ground first?
6 years ago here at the University of
Sydney, I did an experiment very similar
to this where I handed out a heavy
object and a light object and I asked
which one would hit the ground first.
Tell me which one's going to hit the
ground first. I'm going to put my money
on the black fella.
What's your heart telling you?
I reckon it's going to drop faster.
I want the black one as well. Yeah, I'll
go.
Okay.
This one go faster and hit the ground
fast.
This one.
You going to pick that one?
What's your feeling about that one? How
does it compare to the
Well, it's a lot heavier and I just feel
like the weight is, you know, pulling it
down. You know, the more weight it's the
faster it's going to fall to the ground.
The the forces are more on that ball
than this one. You can definitely tell
the difference. I mean, I go to the gym
like 7 days a [laughter] week, but I
still feel it. I can still feel it.
Well, that one feels like it could
almost go up where this one
got it's got air in it. So, the lifting
up as opposed to this one being pulled
down
now. I think now you're coming back to
me. I'm thinking basketball now.
What's making you think basketball? Cuz
you're coming back to me.
Sure.
I'm just saying like
you know I'm I'm going to stay. You
can't corrupt me. I'm going to stay
solid on the black.
All right, let's actually do this thing.
So, do you want to do you want to hook
us up as high as you can? And the key is
to be as simultaneous as you can.
All right. Are you ready? You want to
count it down? Yeah. Three, two, one.
Exactly. [laughter] Oh,
three, two, one.
Yes, we did it.
What did you think happened?
I thought the black one went first.
You thought the black one landed first.
We We'd have to go to the tape. [music]
What did you see?
Uh, they look like they pretty much
landed at the same time.
Same. They hit the ground at the same
time.
Oh, I thought it was very close. It's
probably just a beast it.
It's cuz it's not It's not a very high
distance, so they haven't really reached
their maximum velocity yet.
Well, the black ball just didn't reach
terminal velocity. Wasn't enough time
for it to fall.
I would thought it' be like all the
different variables like um so like that
one had to like break more
air, whatever.
Break more air,
you know?
The answer is although the force of
gravity on the black ball is greater, it
has a greater mass and therefore greater
inertia. So it requires more force to
accelerate it. There's less
gravitational force on the basketball.
But because its mass is lower, it has
less inertia and therefore requires less
force to accelerate it at the same rate
as the medicine ball. Let's give it a
try. Three, two, one.