1 CHAPTER 1

What is physics? it was formerly called natural philosophy, it is concerned with those aspects of nature which could be understood in a fundamental way in terms of principles and laws. So, physics can be defined as the natural science which studies matter, its motion, other related quantities and entities through space and time.

Let's start with the concepts of motion where we shall learn about speed, velocity, acceleration, distance and displacement.

What is motion?- This is the change in the position of a body with respect to time, it has two main categories which are DYNAMICS and KINEMATICS, dynamics is the aspect of motion that deals with motion involving forces. Dynamics is seen in every day life, it even follows Newton's first motion law, examples are- an arrow shot by a person using a bow or a stone thrown/projected by a person. In both examples, forces are applied but what about kinematics?

You are able to change your state of rest and move to another position from where you are standing, right? if so, then what force made you move?- as you can see, no physical force caused that motion. This shows that you normally undergo a kinematic action.

SPEED- It is the rate of change of distance with time, so speed's formula is derived from its definition [Speed=Distance /Time]. Let's take an example : A car traveled a distance of 4000meters in 40 secs. Find the speed

Distance/time=4000/40=100m/s

Also know that speed is a scalar quantity meaning that it has magnitude but no direction