Question

Why are the equations of motion applicable for the analysis of motion under gravity near the surface of the Earth? Assume terms have their usual meanings.

• A. ‘g’ is constant near the earth's surface.
• B. ‘g’ varies near the earth's surface.
• C. ‘G’ is constant varies near the earth's surface.
• D. ‘G’ is constant near the earth's surface.

Answer 1

The correct option is A ‘g’ is constant near the earth's surface.

'G' is universal gravitational constant. It is just a constant of proportionality and does not decide if the motion will be accelerated or uniform.

Near the surface of the Earth, the acceleration due to gravity is approximately constant and it is equal to $9.8m{s}^{-2}$.

Equations of motion are valid for constant acceleration. Therfore, equations of motion are applicable for the analysis of motion under gravity near the surface of the Earth.