00:01
Use data from the moon's orbit from appendix e to compute the moon's acceleration in its circular orbit.
00:09
Well, acceleration in a circular motion is v squared over r.
00:17
The speed of the moon from appendix e is 1 .02 kilometers per second.
00:30
But i'm going to write that as meters per second.
00:39
Okay, so it's v squared.
00:41
And r is also written in kilometers.
00:45
It's 0 .3844 times 10 to the 6th power kilometers.
00:54
But i want to write it as meters, so i'm going to write 10 to the 9th power meters.
01:00
If you put that in your calculator, and i already did, the answer is 0 .5 .5.
01:07
0, 027 meters per second squared.
01:20
Now, in the second part, we're supposed to verify that this result is consistent with newton's laws of gravitation.
01:29
So, i'm going to go to another page.
01:32
We'll just make sure we get the same answer.
01:35
So on second page, newton's laws of gravitation.
01:42
The force is g m1.
01:47
In this case, it's going to be the mass of the earth times mass of the moon over r squared.
01:55
And that's the same as mass times acceleration.
02:04
And this is also the mass of the moon...