Motion Under Gravity

The gravitational force acts in the vertical direction. Therefore, motion under gravity is along a straight line. It is a one dimensional motion. The free fall of a body towards the earth is one of the most common examples of motion with constant acceleration.

In the absence of air resistance, it is found that all bodies, irrespective of their size or weight, fall with the same acceleration. Though the acceleration due to gravity varies with altitude, for small distances compared to the earth’s radius, it may be taken constant throughout the fall. For practical use, the effect of air resistance is neglected.

The acceleration of a freely falling body due to gravity is denoted by g. At or near the earth’s surface, its magnitude is approximately 9.8 ms^–2.