The weight of an object is 90 kg at the surface of the earth. If it is taken to a height equal to half of the radius of the earth, then its weight will become

Options

A. 135 kg
B. 45 kg
C. 60 kg
D. 40 kg

Answer

D

Explanation

Weight of the object at height `h` above the surface of the earth
`w'=(w)/((1+(h)/(R))^(2))rArrw'(h=R//2)=(w)/((1+1//2))`
`rArr w'=wxx(4)/(9)=90xx(4)/(9)=40` kg