# Best 2k19 Defination Of LAW’S OF MOTION

In our everyday life, we observe various types of motion like vechiles moving on a road, flyings birds, movements of needles of a watch, movement of tayer of a car, circulation of blood through arteries and veins etc. Atoms and molecules, planets, stars and galaxies are all in motion.

#### Motion

Motion of a body is its movement and is identified by change in either its location or orientation or both relative to other objects is known as motion.

#### Uniform motion

An object in which the object travels in a straight line and its velocity remains constant along that line as it covers equal distances in equal intervals of time is known as Uniform motion.

#### Non-Uniform Motion

A body is said to have a non-uniform motion, if it travels unequal distances is equal intervals of time, it is said no matter how samll these intervals may be.

#### Newton’s Laws Of Motion

Newton published his law of motion in 1687, in which he formalized the description of how massive bodies move under the influence of external force. Newton’s first law of motion, which state that a body continues to be in a state of rest or of uniform motion in a straight line unless it is acted upon by a net external force. Newton studied the ideas of Galileo regarding the motion of an object. It has published three laws, which describes how forces affect motion of a body on which they act. His three fundamental laws that govern the motion of objects. These law are fundamental in nature in the sense that the first law gives concept of force, inertia and the inertial frame, the second law defines force and the third law action and reaction as two aspects of mutual interaction between two bodies.

### First Law Of Motion

when we rool a cricket baal on a smooth floor, it stops after some time. It is obvious that its velocity decreases and ultimately it becomes zero. However, if we want it to move continuously with the same velocity, a force will have to be constantly applied on it.

or

Every material body has tendency to preserve it state of rest, or of uniform motion in a straight line unless it is compelled to change that state by external forces impressed on it.

#### Inertia

An object to change its state of rest or of uniform motion along a straight line is called inertia of the object.

Inertia is a physical quantity and mass of a material body is measure of its inertia.

#### Inertia of rest, Inertia of motion and Inertia of direction

1:- Inertia Of Rest: The tendency of a body to oppose any change in its state of rest is known as inertia of rest

2:- Inertia of motion: The tendency of a body to oppose any change in its state of uniform motion is known as inertia of motion.

3:- Inertia of direction: The tendency of a body to oppose any change in its direction of motion is known as inertia of direction.

#### Inertial Frame Of Reference

The first aw requires a frame of reference in hich only the forces acting on a body can be responsible for any acceleration produced in the body and not the acceleration of the frameor reference. These frames of reference are known as inertial frames.

### Second Law

Second law of motion states that the rate of change of momentum of an object is proportional to the applied external force and takes place in the direction in which external force acts.

#### Application of second law of motion

The following applications are based on Newton’s second law of motion.

(i) A football kipper moves his hands backward while catching a fast football.

(ii) During race., athletes doing high jump and land on foam or a heap of sand to decrease the force on the body and the landing is comfortable.

### Third law

Force is always a Two-body interaction. The first lw describes qualitatively and the second lw describes quantitatively what happens to a body if a force acts on it, but do not reveal anything about what happens to the other body participating in the interaction responsible for the force.

Newton studied the ideas of Galileo regarding