Gravitation

The weight of a body at a height above the Earth's surface is given by: Given , so: Hence, the height is above the surface, making the total distance from the center of Earth:

Step 1: Understand weight variation with depth
Weight varies with distance from Earth's center as: at surface and above, but follows different rule inside Earth.
Step 2: Gravitational force inside Earth
For points inside Earth (assuming uniform density): where is distance from center.
Step 3: Calculate at midpoint
At midpoint (where is Earth's radius): Given surface weight = 200 N:
Step 4: Verify the proportionality
Using the complete formula for gravitational force inside Earth: At surface ( ):
At midpoint ( ):

In free fall, the only force acting on the object is gravity, which causes a constant acceleration towards the Earth.
This acceleration is called acceleration due to gravity, denoted by , and its standard value near the Earth's surface is approximately .

A satellite is in accelerated motion as it revolves around the Earth due to the centripetal force.
Since it is under the influence of an external force and is not in uniform motion in a straight line, the frame attached to the satellite does not satisfy the conditions of an inertial frame.
Thus, it is considered a non-inertial frame of reference.