00:01
We have to determine the acceleration due to gravity at a point which is at a distance equal to the distance of the moon from the center of earth.
00:11
And the distance of the moon from the center of earth, which is the orbital radius of the moon, is approximately 4 into 10 -res -to -8 meters.
00:19
And we take the radius of earth as 6 .4 times 10 -reast to 6 meters approximately.
00:24
And the expression to get the acceleration due to gravity with respect to the height is g times 1 minus 2h by r.
00:34
And this is an approximate relation.
00:36
So basically we use the idea that acceleration due to gravity is gm over r square.
00:42
So at the surface of earth, this is the value for acceleration due to gravity.
00:47
And let's say the acceleration due to gravity at a distance r, which is the orbital radius of the moon, is g -dash - and that will be gm over r square.
00:57
So from here we can see that g -dash times r -square will be equal to g -times r -square because both these product is equal to universal gravitational constant times the mass of earth...