Physics

# Newton’s Laws of Motion

## Newton’s Laws of Motion

Newton is said to the father of physics. Newton first introduced the law of motion in his book Principal, published in the year 19687.

Newton created the following three laws of motion:

• Newton,s First Law of Motion.
• Newton,s Second Law of Motion.
• Newton,s Third Law of Motion.

### Newton’s First Law of Motion

If an object is in a resting state, it will remain in a resting state and if it is moving in a straight line at the same speed, it will continue to move in the same way, unless its external state is changed by applying an external one. Newton’s law is also called Galileo’s law or the law of inertia.

#### Inertia

Inertia is the tendency of an object to maintain its state of rest or state of equal motion in the absence of externality.

##### Some Prime Examples of Inertia
• When the moving motorcar stops suddenly, the passengers sitting in it lean forward.
• When a stalled motorcar or train suddenly stops, the passengers sitting in it lean backward.
• Holding a blanket or sheet by hand and beating it with a stick, the dust particles fall off.

#### Force

Force is the external factor that changes or attempts to change the initial state of an object.

Force is a vector amount whose SI unit is Newton.

#### Momentum

The product of mass and velocity of an object is called the momentum of that object. Emotion is a vector sign. Its SI unit is kilogram meter per/second.

Momentum = mass*velocity

### Newton’s Second Law of Motion

The rate of change of momentum of an object is proportional to the force exerted that object and the momentum changes in the direction of the force.

F = m*a

(Where F = force, m = mass of the object, a = acceleration produced in the direction of force)

### Newton’s Third Law of Motion

Each action has an equal, but opposite reaction.

For example-

When the shotgun is fired, the driver is pushed backward.

The boat moves backward when jumping the side of the boat.

Rocket blowing.

##### Theory of Momentum Conservation

If no external force is applied to any group or body of particles, the total momentum of that object remains constant. That is, the momentum before and after the collision is equal.

##### Impulse

When a large force acts an object for a short time, the product of the force and time interval is called the impulse of that force.

Right now there is a vector amount whose unit is Newton second.

The direction of the impulse is the same as that of the force.

Impulse = force time = momentum change.

#### What is the Centripetal Force?

When an object moves on a circular path, a force acts on the object towards the center of the circle, which is called the centripetal force.

For example, a motorbike on the wall of a well in the well of death.

In the absence of this force, the object cannot walk on a circular path.

F = mv^2 / r

(Where F = concentric force, m = mass of object, v = velocity and r = radius of circle)

#### What is Centrifugal Force?

This force is called pseudo force or inertial force. Centrifugal force is one such pseudo force or inertial force whose direction is opposite to the centripetal force.

That is, if an object moves on a circular path, then the force acting outward from the center of the circle is called the centrifugal force.

In the absence of this force, the object cannot walk on a circular path.

#### What is the Moment of Force?

The tendency of a body to rotate an axis by force is called force moment.

The force moment is equal to the magnitude of the force and the vertical distance between the action line of the force from the axis.

Force moment is a vector amount whose unit is Newton meter.

#### What is the Simple Machine?

A simple machine is a device in which the load placed on another point is carried by applying force on a convenient point.

Such as – lever, pulley, inner floor, screw, jack, etc.