800 lb space probe is launched from Earth, headed for deep space. a) List the correct equation and solve for mass given that the acceleration of gravity is 32.2 ft/s2

b) At a distance of 15,000 miles from the Earth's center, the space probe releases a payload that reduces the mass of the space probe by 1/4th (i. e., space probe is now 25% lighter in mass). By how much did the gravitational force go up or down after the payload has been released? Start with the equations from the text or class notes and solve.