Types of motion
In our day‒to‒day life the following kinds of motion are observed:
An object is said to be in linear motion if it moves in a straight line.
· An athlete running on a straight track
· A particle falling vertically downwards to the Earth.
Circular motion is defined as a motion described by an object traversing a circular path.
· The whirling motion of a stone attached to a string
· The motion of a satellite around the Earth
These two circular motions are shown in Figure 2.5
If any object moves in a rotational motion about an axis, the motion is called ‘rotation’. During rotation every point in the object transverses a circular path about an axis, (except the points located on the axis).
· Rotation of a disc about an axis through its center
· Spinning of the Earth about its own axis.
These two rotational motions are shown in Figure 2.6.
If an object or particle executes a to-and- fro motion about a fixed point, it is said to be in vibratory motion. This is sometimes also called oscillatory motion.
· Vibration of a string on a guitar
· Movement of a swing
These motions are shown in Figure 2.7
Other types of motion like elliptical motion and helical motion are also possible