Question

The weight of an object varies inversely as the square of its distance from the centre of the earth. The weight of an aeroplane is observed to be only 4/9 of its weight on earth. How far is the aeroplane from the surface of the earth. Take the radius of the earth to be 6400km

Answer 1

aeroplane ... or space capsule?

inverse square root of 3/2

(3/2 * 6400) - 6400

Answer 2

woof ... not fully awake yet

inverse square root of 4/9 is 3/2

(3/2 * 6400) - 6400 = ?

Answer 3

W=k/d^2.
Distance = r+R.
Distance from the centre, r=0
W=k/R×R
K =W×R×R
W=w×R×R/(r+R)^2
4W/9=(W×R×R)/(r+R)^2
4W(r+R)^2= 9×W×R×R
4(r+R)^2=9×R×R
(r+6400)^2= 9×6400×6400/4
r+6400= 9600
r = 9600-6400
r=3200km