Newton's Law of Gravitation says that the magnitude F ofthe force exerted by a body of mass m on a body of massM is the following, whereG is the gravitationalconstant and r is the distance between the bodies.
(a) Find dF/dr. dF/dr =
(b) Suppose it is known that Earth attracts an object with a forcethat decreases at the rate of 2 N/km when r = 20000 km.How fast does this force changewhen r = 10000 km? N/km