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Fields in Space Videos 15 videos
Don't let this question about gravitational forces get you down! Yeah, yeah...that was an easy joke. You get what you pay for.
AP Physics 1: 2.1 Fields in Space. What are the units for the universal gravitational constant G?
We've heard of some crazy dieting fads, but leaving the planet may take the cake. We don't suggest you do that, but we do suggest you answer t...
AP Physics 1: 3.3 Fields in Space 173 Views
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Description:
Maybe if the dinosaurs had paid more attention in AP Physics, they could've figured out a way to avoid that pesky extinction problem. Oh well. Solve this question in fond memory of all the dinosaurs.
Transcript
- 00:03
Here's your shmoop du jour brought to you by mad scientists worried you're
- 00:07
going mad? take a second to watch some cute cat [White cat appears]
- 00:09
videos you know those always take the edge off for us alright
- 00:13
Igor is working in his laboratory when he peers into his telescope and spots a
- 00:18
large asteroid working feverishly he calculates that the asteroid is twenty [Asteroid and earth collision drawing]
Full Transcript
- 00:22
thousand kilometers away from the center of the earth
- 00:25
what's the magnitude of gravitational force that the earth exerts on the
- 00:30
asteroid huh and here the potential answers....... Igor is stressed but we
- 00:36
can't blame him, there's an asteroid out there and he needs to make sure [Asteroid heading towards Earth]
- 00:39
everything stays groovy here on earth now in order to answer this question we
- 00:44
need to remember the formula to figure out gravitational force that equation
- 00:48
goes a little something like this gravitational force is equal to the [Gravitational force equation appears]
- 00:51
gravitational constant G times the mass of the larger object M divided by the
- 00:59
square of the distance between the objects that distance here is the radius
- 01:03
which is shown as R in the equation right there so GM over R squared now the
- 01:08
question doesn't tell us what the mass of the earth is the only number we know
- 01:12
for sure is the distance between the asteroid and the center of the earth
- 01:15
which is 20,000 kilometers so we need to square that number in order to calculate
- 01:20
the gravitational force but wait we need to convert those kilometers into meters
- 01:25
we've got to use standard units because well they're standard for a reason [standard units appear]
- 01:29
20,000 kilometers is 20 million meters and 20 million squared is 400
- 01:35
quadrillion so the correct answer here is D) and boy that's a whole lot of
- 01:40
meters now to answer question like this we need to memorize the equation there's [Boy's head opens and equation appears]
- 01:43
no way around it people now listen carefully...G equals GM over R squared G
- 01:50
equals GM over R squared...... G equals GM over R squared
- 02:00
and now we're starting to understand why scientists go mad
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