# 亚博网址多少

Physics

Wave interference
Beats
Doppler Effect

Laser
Transverse & longitudinal waves

# Motion

The continuous change in position of a body with respect to time and relative to the reference point or observer is called motion. Here the reference point can be considered as stationary or motionless objects surrounding the body.

Example :

Consider sun as reference point or observer the planets orbiting the sun are said to be in motion.

The position of a body is not changing with time and relative to the reference point then the body is said to be at rest or motionless. chairs, tables, Television are some examples of objects which are at rest. Rest and motion are relative terms for example consider a person in a moving bus he is at rest with respect to another person in the moving bus, but he is in motion with respect person out side the bus.

## Uniform motion

When a body moves equal distance in equal intervals of time then the body is said to be in uniform motion.
Example :

A train travels 10Km distance  at first 10min(minutes) and the next 10min(minutes) the train covers the same 10Km distance then the train is said to be at uniform motion.

Speed of light in vacuum is an example of uniform motion.

## Non uniform motion

When a body moves unequal distance in equal intervals of time then the body is said to be in non uniform motion.
Example :

A train travels 10Km distance in first 10min(minutes) and the next 10min(minutes) the train travels 20Km then the train is said to be in non uniform motion because after the first 10min the speed of train gets increased so the train is not traveling at constant speed.

## Periodic motion

When the motion is repeated for a fixed period of time then the motion is said to be periodic motion. For example planets orbiting the sun is called periodic motion because planets are moving in  the same path continuously.

## Oscillatory motion

The oscillatory motion is a specific type of periodic motion in which a body moves back and forth I.e. either up and down or front and back for a fixed period of time from the initial point.