Newton's Second Law: Newton's Second Law states that the net force acting on an object is equal to the object's mass multiplied by its acceleration, which is the mathematical expression $a = F_{net} / m$.
Inertia:Inertia is the property of an object that resists changes in its motion, and is directly related to the object's mass. The greater an object's mass, the greater its inertia and the more net force is required to change its motion, as described by $a = F_{net} / m$.
Momentum:Momentum is the product of an object's mass and velocity, and is conserved in the absence of net external forces. The equation $a = F_{net} / m$ is used to relate changes in an object's momentum to the net force acting on it.