Kind: captions
Language: en
All right, are you ready for the moment
of truth? Let's drop these two objects
at exactly the same time and see which
one hits the ground first. Ready? Three,
two, one.
Wow. Did you see that? The one connected
to the chain landed just before the
other free weight. I'd like to show this
in slow motion so you can see that the
weights are accelerating at just
slightly different rates. Heat.
Heat.
[music]
Why did that happen? I mean, most
people, most students of physics would
know that all objects on Earth's surface
should accelerate down at the same rate,
9.8 meters/s squared. But in this case,
what happens is the chain actually whips
the weight around. So it accelerates at
a rate greater than the acceleration of
objects when in freef fall. That's a
pretty remarkable result. I want you to
think about the bend in the chain. As
the weight descends, the chain goes from
falling to becoming stationary. So it's
accelerating up. The tension required to
accelerate the chain up actually pulls
down on the weight, accelerating it at a
rate greater than the acceleration due
to gravity. and that's why it hits the
ground first. Now, this actually happens
to bungee jumpers. If the weight of the
rope is appreciable, they will actually
accelerate down at a rate faster than
freef fall, faster than 9.8 m/s squared.
When I went bungee jumping, I was aware
of this. What is actually true is that
as you fall, your acceleration will be
greater than free fall. And that's due
to some uh effects of the the way the
rope pulls on you. So, I'll do an
explanation of that later when I'm not
scared out of my mind.
3 2 1 Oh my god.
[laughter]
[screaming]
I couldn't figure out what the
acceleration was as I was going down,
but you know, it felt high. It felt very
fast. Very great increase in in your
rate of speed. So,
oh my god, that was fast.
Loved it.