Physics Problem 6.20
posted by Michael Moskvich .
The center of a 1.40 km diameter spherical pocket of oil is 1.50 km beneath the Earth's surface.
Estimate by what percentage g directly above the pocket of oil would differ from the expected value of g for a uniform Earth? Assume the density of oil is 8.0*10^2kg/m^3.
Express your answer using two significant figures.

Gravitational field= GMe/re^2Mass/700^2 + G Massoil/700^2
= 9.8N/kg+ G/700^2 (volumemhole)(densityoildensityEarth)
= 9.8+G/490000 * 4/3*PI*700^3 (8006000)
(I estimated Earth density at 6times that of water)
= 9.8+6.67E11/4900 (1.44E9)(5200)
=9.8.12 or 9.7N/kg
check all this.