- #1
pierce15
- 315
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Homework Statement
Inside the earth, the force of gravity is proportional to the distance from the center. If a hole is drilled through the Earth from pole to pole and a rock is dropped in the hole, with what velocity will it reach the center?
The Attempt at a Solution
I think that the proper way to set it up is
[tex] \frac{ d^2 x}{dt^2} = C (R - x), [/tex]
where R is the radius of the earth. Then, since the acceleration is ## g ## when the rock is at R, aka when x = 0, C must equal g / R. Thus, the equation is
[tex] \frac{d^2 x}{dt^2} = \frac{ g}{R} (R-x) [/tex]
Is this the correct way to proceed?
[tex] \int \frac{d^2 x}{g/R (R - x)} = \int dt^2 [/tex]