Question : What is the basic difference between inertial mass, gravitational mass and weight of a body?
Doubt by Tanany
Solution :
Inertial Mass : The mass of the body which determines its inertia in a translatory (straight line) motion. It is a measure of object's resistance to change its state of motion. The more inertial mass an object has, the more force is required to accelerate it. It is defined by Newton's second law of motion.
F=mia
mi=F/a
It is also defined as the ratio of the external force applied on the body to the acceleration produced in it.
It can be measured by using an inertial balance.
Gravitational Mass : The mass of a body which determines the gravitational pull acting on it due to the earth is called its gravitational mass. The more gravitational mass an object has, the stronger will be its gravitational pull.
It is defined by the Newton's Universal Law of Gravitation
F=GMmg/r²
Fr²/GM=mg
mg=Fr²/GM
where mg is the gravitational mass of the body. It is measured by using a physical balance.
Weight : It is the force of gravity that earth (or any other planet) exert on the body. The weight of an object depends on its gravitational mass and the strength of the gravitational field in which the body is placed.
Note :
1) Inertial mass and gravitational mass are always equal to each other.
2) The SI unit of inertial and gravitational mass is kilogram (kg) while the SI unit of Weight is Newton (N).
3) Inertial mass and Gravitational Mass both are independent of gravitation field in which they are placed but the weight of the body does depend on the gravitational field in which the body is placed.