(a) Show that the rate of change of the free-fall acceleration with distance above the Earth’s surface is dg/dr = 2GME/RE3 This rate of change over distance is called a gradient. (b) If h is small in comparison to the radius of the Earth, show that the difference in free-fall acceleration between two points separated by vertical distance h is |Δg| = 2GMEh/RE3 (c) Evaluate this difference for h = 6.00 m, a typical height for a two-story building.