The inertial mass of an object determines its acceleration in the presence of an applied force. According to Newton's second law of motion, if a body of fixed mass M is subjected to a force F, its acceleration α is given by F/M. A body's mass also determines the degree to which it generates or is affected by a gravitational field. If a first body of mass MA is placed at a distance R from a second body of mass MB, each body experiences an attractive force Fg = GMAMBR/|R|3, where G=6.67×10−11 N kg−2m2 is the "universal gravitational constant". This is sometimes referred to as gravitational mass.[note 1] Repeated experiments since the 17th century have demonstrated that inertial and gravitational mass are equivalent
Inertial mass is a measure of an object's resistance to changes in its motion, while gravitational mass is a measure of the strength of an object's gravitational pull. In other words, inertial mass determines an object's response to a force, while gravitational mass determines an object's response to gravity.
The equivalence principle states that the inertial mass of an object is equal to its gravitational mass. This means that all objects, regardless of their mass, fall at the same rate in a gravitational field.
Understanding these concepts is crucial in understanding how objects move and interact in the presence of gravity. It also plays a key role in the theory of relativity and helps explain the behavior of objects in the universe.
Inertial mass can be measured by observing an object's acceleration in response to a known force. Gravitational mass can be measured by observing the strength of an object's gravitational pull on another object. The two masses are typically found to be equal.
According to the theory of relativity, mass can be converted into energy and vice versa. However, the ratio between an object's inertial and gravitational mass remains constant, regardless of any changes in the object's energy or state.