Question

A man weighs 600n on the surface of the earth . At what height above the surface of the earth will be weigh 300n? Take radius of the earth.6400 km

Answer 1

Answer:

the correct answer is 1600 km above the surface of earth

Answer 2

Answer and Explanation :

Let m be mass of man. Let g and g' are acceleration due to gravity on earth's surface

and at a height above earth's surface respectively

Weight of man on earth's surface = m×g = 600 N ...............(1)

Weight of man at a height above earth's surface = m×g' = 300 N .............(2)

from (1) and (2), we get

g=GM/R(sq.)= (R + h)(Square)=2 .....(3)

g'GM/(R + h)(sq.) R(Square)

G is gravitational constant, M is mass of earth and R is radius of earth.

By solving eqn.(3) for h, we get

h= R / (1 + (underoot 2) )

= 6400 / ( 1 + ( underoot 2) )

= 2651km