Near the Earth’s surface it is common to treat the gravitational field strength as uniform
PHYSICS · Multi-part · AP · Physics 1: Algebra-based · Force and Translational Dynamics · Force and Translational Dynamics
Problem
Near the Earth’s surface it is common to treat the gravitational field strength g as uniform, even though g actually decreases with distance from Earth’s center.
(1) Part 1: (a) Using the expression g=GME/r2, describe qualitatively how the magnitude of g changes as an object’s distance r from Earth’s center increases.
(2) Part 2: (b) Explain, without performing numerical calculations, why the approximation g≈constant is typically adequate for motion that remains within a few kilometers of Earth’s surface.
(3) Part 3: (c) The International Space Station orbits approximately 4.0×102km above Earth’s surface. Using your reasoning from parts (a) and (b), discuss whether the constant–g approximation would be appropriate for analyzing the orbital motion of the station. Provide a clear explanation that references how g varies with altitude.