Newton’s Laws of Motion:-

Newton’s Laws of Motion:-
   These principles can be wrapped up in just three statements that were clearly stated for the first time by Sir Isaac Newton (1642-1727), who published them in 1687 in his philosophiae Naturalis principia Mathematica (“Mathematical Principles of Natural Philosophy”). These three statements are called  Newton’s Laws of Motion. The first low stated that “When the net force on a body is zero, its motion doesn’t change”. The second law relates the force to acceleration when the net force is not zero. The third law is a relationship between the forces that two interacting bodies exert on each other. (Newton used the ideas and observation of many scientists before him, including Copernicus, Brahe, Kepler, and especially Galileo Galilei, who died the same year Newton was born). Newton’s laws are empirical laws, deduced from experiments. Newton’s laws are adequate for speeds that are low compared with the speed of light when the bodies move with the speed of light then Newton’s laws failed like atomic particles in an accelerator relativistic mechanics developed by Albert Einstein is applicable.

Types of Frame of Reference:-

Types of Frame of Reference:-
There are two types of frames of reference.
Inertial frame of reference
Non-inertial frame of reference.
Inertial Frame of Reference:-
Definition:-
The frame of reference in which Newton’s first law of motion holds good is called inertial frame of reference.
Non-inertial Frame of Reference:-
Definition:-
The frame of reference in which Newton’s first law of motion does not hold good is called non-inertial frame of reference

What is inertia?

Inertia:-
“The property of matter due to which it resists its state of rest or of uniform motion is called inertia” OR

“The tendency of a body to keep moving once it is set in motion results from a property called inertia”.

Newton’s First Law of Motion

Newton’s First Law of Motion:-
“Every object continues its state of rest or uniform motion in a straight line unless it is compelled to change that state by external forces acting upon it”. This is also known as law of inertia.
                                                                         OR
“A body acted on by no net force moves with constant velocity (which may by zero) and zero acceleration”

Q.No.1:- Explain what do you understand by the term viscosity?

Ans:-
From the microscopic study of flowing fluid we know that fluid flows when the layers of fluid slid over on another. But there exists another opposing force between the layers of fluid which wants to stop this sliding. This force is called the viscosity.
In short we can say that viscosity is the opposing force (frictional effects between the relative motion of layers of fluid) between the layers of fluid which will slow down the flow of fluid or stop it if it is very large.