Define inertia and list its types. Give two examples to describe each type. On what factors inertia depends?
Answers
Answer
It is the inability of a body to change its state of rest, motion or its direction by itself.
There are three types of motion :
(a) Inertia of rest
It is the inability of a body of change its state of rest by itself.
Example :
» When the driver starts the bus suddenly, the pássenger standing in a rest experience a backward jérk. This happens because the feet of the pássenger in contact with the bus comes into motion but the upper part of the body continues to be at rest due to inertia of rest.
(b) Inertia of motion
It is the inability of a body of change its state of motion by itself.
Example :
» When the driver stops the bus suddenly, the pássengers standing in a moving bus experience a forward jérk. This happens because the feet of the pàssenger in contact with the bus comes to rest along with the bus the upper part of his body continues its motion due to inertia of motion.
(c) Inertia of direction
It is the inability of a body of change its direction of motion by itself.
Example :
» When the stone is tied to one end of a string is rotated circularly and the string break then stone flies along the tangent to the circle. This happens because the pull in the string was forcing the stone to move in a circle. As the string breaks the pull vanishes due to inertia of direction.
Inertia depends on the mass of the mass. Mass is a measure of inertia in transtatory motion. Heavier the mass, larger the inertia and vice versa.