Free Fall motion and projectiles motion | POINT classical mechanics

 Free fall and projectile motion are fundamental topics in classical mechanics that provide clear insights into the nature of motion under the influence of gravity. In free fall, an object moves solely under the force of gravity, experiencing a constant acceleration downward, typically ignoring air resistance. In contrast, projectile motion involves an initial velocity at an angle, resulting in a curved, parabolic trajectory as the object moves both horizontally and vertically. These phenomena not only illustrate the predictable behavior of objects in a gravitational field but also serve as a basis for more complex analyses in physics, engineering, and various real-life applications.

Free Fall:

When two objects of different masses (a book and a paper) fall from the same height above the ground, these two objects begin their movement from rest (0) - (7) heading downward under the influence of:

(1) The force of the earth's attraction to them (their weight).

(2) Air resistance, where air molecules collide with the object and affect the speed of its descent, and its effect appears more in the case of light objects, Therefore, the book reaches the surface of the earth faster than the paper.

If we neglect air resistance, the two bodies fall under the influence of their weight only, so they acquire a constant, regular acceleration that gradually increases the speed and they reach the surface of the earth at the same moment. This acceleration is called the acceleration of gravity (the acceleration of free fall), which is the regular acceleration that objects move with during their free fall towards the surface of the earth.

The acceleration of free fall varies slightly from one place to another on the surface of the earth because the earth is not completely spherical, but rather flattened at the poles, and thus the value of the acceleration of free fall varies according to the distance from the center of the earth.

The value of the acceleration of free fall is equal 9.8 m/s²,or for simplicity it can be considered am 10 m/s²

Scientists who benefited humanity

Galileo Galilei

Galileo:

When Galileo dropped two objects of different masses from the top of the Leaning Tower of Pisa in Italy, he found that, neglecting air resistance, objects of different masses reach the Earth's surface at the same moment

Thus, he broke Aristotle's idea that:
"Objects with large masses reach the Earth's surface in less time than
Objects with small masses"

*The equations of motion with uniform acceleration are applied to objects moving in the Earth's gravitational field by compensating for the acceleration (a) with the acceleration of free fall (g):

Vf = Vi + gt

d = Vt + ½ (gt)²

2 gd = Vf² - Vi²

When an object falls from top to bottom:
The initial velocity of the body is equal to zero (Vi = 0) and its velocity increases gradually until it reaches its maximum value at the surface of the Earth.