Answer:
We can use optical fibers.
Explanation:
The optical fibers are the optical devices which is based on the total internal reflection.
The optical fiber has two layers, one is called core and the other is called cladding.
The refractive index of core is more than the cladding.
As a ray of light falls on the core at more than the critical angle for that pair of media(core and cladding), it suffers the total internal reflection at the interface.
Given,
Distance from the surface to the center of the earth, d=4000 miles
Distance from the center to you at a height of 8000 miles, a= 8000+4000=12000 miles
The gravitational force acting on a person at the surface is equal to his weight.
From Newton's Universal Law of Gravitation, the gravitational force is
Where G is the gravitational constant, M is the mass of the earth, m is the mass of the object/person, r is the distance between the center of the earth and the object/person
At the surface, this force is equal to the weight of the person, W=mg
i.e.
On substituting the of d,
At a height of 8000 miles from the surface, the gravitational force is equal to,
On dividing the above two equations,
Therefore,
Therefore at a height of 8000 miles above the surface of the earth, the force of gravity becomes 1/9 time your weight.