take ANY 2 random objects

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take ANY 2 random objects
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take ANY 2 random objects
like an apple
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take ANY 2 random objects
and the earth
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take ANY 2 random objects
ignore everything else
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See What Happens
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(No Transcript)
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WHY?
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Universal Gravitation
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Verbally
Gravity is a force that pulls any objects with
mass together! The bigger the masses the harder
it pulls. The closer the masses the harder
gravity pulls.
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Mathematically
Fg
Fg
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Universal Gravitation
Fg the force of gravity between object A and
object B G the gravitational constant mA the
mass of random object A mB the mass of random
object B d the distance between object A and
object B
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Universal Gravitation
Fg the force of gravity between object A and
object B G the gravitational constant mA the
mass of random object A mB the mass of random
object B d the distance between object A and
object B
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Universal Gravitation
Fg the force of gravity between object A and
object B G the gravitational constant mA the
mass of random object A mB the mass of random
object B d the distance between object A and
object B
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Universal Gravitation
Fg the force of gravity between object A and
object B G the gravitational constant mA the
mass of random object A mB the mass of random
object B d the distance between the centers of
objects A and object B
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Universal Gravitation
Fg the force of gravity between object A and
object B G the gravitational constant mA the
mass of random object A mB the mass of random
object B d the distance between object A and
object B
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Your LUCKY Day!

• The Gravitational Constant
• is
• ALWAYS
• the same number

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In Case Theyre Not in Your Notes Yet!

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Time for an Example
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Time for an Example

• We already know
• Fg mg
• Now we also know

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Time for an Example

• Lets think about
• any random object A
• then
• Fg mAg

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Time for an Example

• Put it together with

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Time for an Example

• And we get

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Time for an Example

• Luckily the mAs cancel out

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Time for an Example

• Then were left with

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Time for an Example

• If random object B is the earth
• mearth 5.98 x 1024 kg

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Time for an Example

• And if random object A

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Time for an Example

• And if random object A

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Time for an Example

• And if random object A
• is sitting on the earth

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Time for an Example

• And if random object A
• is sitting on the earth

The distance is the radius of the earth
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Time for an Example

• And if random object A
• is sitting on the earth

d 6.38 x 106 m
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Time for an Example

• Plug in
• mearth 5.98 x 1024 kg
• d 6.38 x 106 m
• G 6.67 x 10-11

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Time for an Example

• You get

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Time for an Example

• Which gives us something familiar

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Your Turn

• Go get the worksheet
• Universal Gravitation
• from the front table.

YOU Get to find g on the moon.