Kind: captions
Language: en
most people recognize that the
gravitational force attracts them
towards the Earth and keeps them stuck
on the
planet but the gravitational force does
so much more than that it attracts any
object with mass towards any other
object with mass so for example this
table is attracted gravitationally to
the chair and the chair is attracted to
the table this this is a beautiful
symmetric idea because it means that
every object you can see around you is
attracted to you gravitationally and you
are attracted to it the reason we don't
notice that attraction is because the
force is so small so today I'd like to
show you how to calculate the size of
the force of attraction between any two
masses so in this example we'll call
this Mass one and this object Mass 2
the force is proportional to mass one so
the larger Mass one is the bigger the
force is the force is also proportional
to mass two the bigger that mass is the
bigger the force is now the force is
what we call inversely proportional to
the distance between them squared so if
the distance between their centers is
called r are then the further apart they
are the smaller this force is and that
makes
sense now to make this a true equality
we need to add Big G the universal
gravitational constant this is just a
number a constant of the universe which
tells us how strong the gravitational
force is this number G is
6.67 * 10 the
-1
Newton m squar per kilogram
squar as you can see it's a pretty small
number so the force is going to be
relatively small so let's do an example
let's calculate the force of attraction
between me and say hello de this is my
twin brother Hi
everybody so the force f is going to be
equal to the gravitational constant 6.6
7 * 10
-1 time my mass which is 70 kg * de's
Mass which is 70 kg oh no I thought you
were putting on a little weight no hey
70 70
kg and divide by the distance between us
which is what do you say about 1.5
M don't forget to square it I wasn't
going to
forget okay so this work works out to be
1.45 * 10
-7 Newtons there is a 10th of a
millionth of a Newton attracting me and
deck and that's not all
dude now A newton is the amount of
attracted to
me