Inertial mass measures resistance to acceleration under force, while gravitational mass determines the strength of gravitational interaction. Both are equal, ensuring the equivalence principle in physics.
Class 11 Physics
Gravitation
CBSE EXAM 2024-25
Inertial mass and gravitational mass are two of the most basic concepts in physics, explaining properties of matter but different in their measurement phenomenon.
Inertial mass is the definition of resistance that an object poses for changes in its motion once a force is applied on it. It quantifies the difficulty to accelerate an object. For instance, a more massive object with greater inertial mass will require much more force to achieve acceleration of equal magnitude to a less massive object. This concept was deeply placed in Newton’s second law of motion and measured in dynamic experiments involving motion and force.
On the contrary, the gravitational mass sets the intensity of interaction an object exhibits with the gravitational field. It expresses the degree to which an object experiences the force of gravitation by being at a given distance from some other heavy body such as Earth or the Sun. Gravitational mass is normally gauged by either gravitation between objects or its weight within a gravitational field of known strength.
Interestingly, inertial and gravitational masses are observed to be equal experimentally. It means they give the same numerical value for the same object. This is a principle of Einstein’s general theory of relativity, suggesting that gravitational force and acceleration can’t be distinguished in certain situations. Although they are conceptually different, the equality of these masses simplifies our understanding of motion and gravity in the universe.