SOLUTION: Need help with this calculus problem: Newton's Law of Gravitation says that the magnitude F of the force exerted by a body of mass m on a body of mass M is F = GmM/r2 dF/dr

Question 915039: Need help with this calculus problem:
Newton's Law of Gravitation says that the magnitude F of the force exerted by a body of mass m on a body of mass M is
F = GmM/r2
dF/dr = -2GmM/r^3
(b) Suppose it is known that the earth attracts an object with a force that decreases at the rate of 4 N/km when r = 30,000 km. How fast does this force change when r = 15,000 km?
Answer by Edwin McCravy(20055) (Show Source): You can put this solution on YOUR website!

(b) Suppose it is known that the earth attracts an object with a force that decreases at the rate of 4 N/km when r = 30,000 km.



Substitute -4 for  and 30000 for r







Substitute  for  in





How fast does this force change when r = 15,000 km?

Just substitute 15000 for r in







Edwin

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