The force and newton's First Law (Inertia) | POINT classical mechanics
The force, Newton's first law, And intertia
Exploring the concepts of force, Newton's First Law, and inertia provides valuable insight into how objects interact in the physical world. By examining the interplay between applied force and an object's inherent tendency to resist change, we can appreciate the framework that underpins much of classical mechanics. This discussion focuses on the dynamic relationship between external influences and the natural stability of objects, inviting us to consider how these fundamental ideas shape our understanding of motion.
We have previously studied the description of the movement of objects through the concepts of speed and acceleration without discussing the causes of that movement, and in this chapter we will discuss these causes (force).
Force:
Is an external influence that affects the body and changes or attempts to change its state or direction.
Examples:
- Your muscle strength helps you move objects.
- The power of the car engine helps to start the movement.
- The power of the brakes helps to stop the car.
Scientists who have benefited humanity
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The two great scientists Galileo and Newton are credited with developing an organized theory of motion in the seventeenth century, where they explained and interpreted the causes of the movement of objects and how they move.
Newton's Laws of Motion
Newton's first law:
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When a ball is placed on the field, it remains stationary in place unless the player moves it (unless an external force affects it and changes its state
When the ball is kicked, it moves a certain distance and then slows down until it stops after a while because the ball is affected by an external force that changes its state (motion), which is the frictional forces between it and the ground that resist the movement of the ball. In the absence of these forces, the ball will continue to move at a constant velocity in a straight line.
That is: the body needs a force to change its state from rest to motion or from motion to rest, but it does not need a force to maintain its state (rest or motion at a constant speed in a straight line.
From the above, we can conclude the text of Newton's first law:
The body remains in its state of rest or motion at a constant speed in a straight line unless a resultant force affects it changes its state.
The mathematical formula for Newton's first law:
ΣF = 0
(The symbol (Σ) is called sigma and means resultant)
That is: If more than one force affects a body so that they cancel each other out, so the resultant of the forces (ΣF) affecting this body becomes zero, then the acceleration equals zero (0 = a), so the speed of the body does not change whether it is stationary or moving.
Inertia
Newton's first law is related to the concept of inertia.
The concept of inertia can be illustrated through the following examples:
1- The coin falls into the cup when the paper is suddenly pushed Because the stationary body tries to maintain the state of rest it was in
2- The motorcycle driver rushes forward when it hits a barrier. Because the moving body tries to maintain the state of motion it was in.
3- The fan continues to rotate for a period of time after the power has been cut off. Because the moving body tries to maintain the state of motion it was in.
So Inertia: is the tendency of a body at rest to remain at rest and the tendency of a body in motion to continue moving at its original velocity in a straight line.
or
The property of objects resisting changing their state from rest to motion.
(1) Newton's first law is called the law of inertia because the body is unable to change its state (from rest to motion at a constant speed in a straight line).
2) A seat belt must be worn while driving a car to reduce the body’s sudden forward thrust during a collision due to its inertia, which reduces the rate of injuries.
Technology adaptation
Space rockets do not consume fuel after leaving the Earth's gravitational field because the inertia self works to continue its movement at a constant speed and in a straight line.
to continue to newton's second law and momentum
In summary, the interrelationship between force, Newton's First Law, and inertia provides a clear and coherent framework for understanding motion. Recognizing that objects maintain their state of rest or uniform motion unless influenced by an external force not only simplifies the analysis of everyday phenomena but also forms the basis for more complex scientific inquiries. This foundational perspective reinforces the elegance of classical mechanics and underscores its relevance in both theoretical studies and practical applications, guiding our interpretation of the natural world and technological advancements.