2 satelites A & B are in orbits 6400km & 12800km above the earth's surface respectively.?

Question

The gravitational force experienced by A how many times that by B?
(EXPLAIN HOW)

Answer 1

Force = G m1m2 / r^2

So if you A has half the force of B, what happens to the force?

Answer 2

You need to add the radius of the earth to those distances and call them d1 and d2. The gravitational force is inversely proportional to the square of the distance d. So, in this case, d2 is not double d1 because the earth's radius is added. If it were double, the force would be 4 times less. Force reduces as we go away from earth.

Answer 3

The force experienced by the setellite A
= G. Mass of earth * mass of setellite /(radius of earth + 6400000)^2
the force experienced by setellite B
= G*mass of earth * mass of setellite B/(radius of earth + 12800000)^2

So the ratio (considering the two mass of setellites to be same is
force on A/force on B =

(Radius of earth+12800000)^2/(radius of earth+6400000)^2

***Do not make mistake by taking simple ratio of heights. The distance is always from the centre of the earth.

(The radius of earth is 6400 Km) so in the above case,
the ratio is
6400000+12800000)^2/6400000+6400000)^2
=3^2/2^2
= 9/4
the ratio is 9:4