Motion | One Dimension Motion (Straight Line Motion)

Motion

Frame of reference

If we need a co-ordination to determine the speed or position of a particle and its motion, from which the coordinates of particle or object (x,y,z) express the position of motion or particle relative to the original point. In such co-ordination Frames, there should also be a system to measure time, for which the position of object can be unique evaluated on different moments. Such instruction frames are called space-time co-ordinate frames. Generally there are two types of co-ordinates frames, Inertial and non-inertial.

Inertial co-ordinate 

Inertial co-ordinate system are those co-ordinate system in which they follow Newton's law. In other words those Co-ordinate system which are in motion or in rest they all are in absolute velocity are called Inertial co-ordinate system.

Non Inertial co-ordinate

Non Inertial Co-ordinate System are such co-ordinate system in which they do not follow Newton's law.

Rest and Motion

What is Motion? Without speed, we can not imagine life. We need a motion to do the smallest or biggest work of our life. Whether it was writing on copy or playing cricket match, there is motion in every work or Motion is necessary for doing all the work. Every body in this universe is in motion. In our day-to-day life we see bodies moving around us. for example car moving,people dancing-walking, animals running etc. A book placed on the table we say that the book is at rest. because the book does not change its position as time passes. However, if we look from the moon , the whole earth is change its position with time passes, so the room, table, and the book are also continuously changing their positions with time. When we look from the moon, we see the book in motion and if we look from the earth, then the book looks at rest.

Thus, a body is said to be at rest if it does not change it position with time, while a body is said to be in motion if it changes its position with respect to time.

Distance and Displacement

Distance is the way through which an object or particle travels to its destination, while displacement is the distance  from the initial point to the final point.
Suppose an moving object (or a particle) first goes from O to P point and then returns from P to Q. Now the distance covered by a particle O to P is OP = 90 meter and the distance covered by P to Q is PQ = 20 meter, so the distance covered by the particle from O to P and P to Q is OQ = 110 meters. Therefore, direction is the not given importance for expressing distance. So distance is a Scalar quantity. But if we also consider direction than the distance covered by the particle is equal to OQ is 70 meters.