- #1
takando12
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- 5
Homework Statement
The value of g at a point P inside the Earth and at another point Q outside the Earth is g/2. Maximum possible distance in terms of radius of Earth between P and Q is? (g being the acceleration due to gravity on the surface).
Homework Equations
gh = (1+h/r)-2g
gd = (1-d/r)g
The Attempt at a Solution
I don't understand what maximum distance is. The value of g reduces whether we go above or below the Earth's surface and there is only one point above and below that correspond to g/2 and so there is only one distance between those two points. How does maximum distance come into this?
Just using the formulas I get:
d= R/2
h = R(√2-1) or -R(√2+1) // what does that negative sign actually mean in the second one?
Distance between the two points =
-(2√2+1)R/2 or (2√2-1)R/2 // again a negative sign.
And I suppose maximum means I should choose the first and the answer is right. But I just don't get what the answer means. How can there be more than one distance between P and Q? What do those negative signs mean?
Please point out where my understanding is flawed.