1. The problem statement, all variables and given/known data a) Find the altitude above the Earth's surface where Earth's gravitational field strength would be two-thirds of its value at the surface. Assume re = 6.371 103 km. __________ km (b) Find the altitude above the Earth's surface where Earth's gravitational field strength would be one-third of its value at the surface. ___________km [Hint: First find the radius for each situation; then recall that the altitude is the distance from the surface to a point above the surface. Use proportional reasoning.] 2. Relevant equations This is what I am having trouble with. What equation do I use? 3. The attempt at a solution I am having trouble with the equation. Which equation do I use for gravitational strength that involves height...or distance from the surface of the earth??