Momentum vs Inertia
Both momentum and inertia are basic components of physics.
Momentum is a component of classical mechanics which refers to the product of mass and velocity of a particular object. Inertia, on the other hand, is a component of classical physics which refers to the resistance of any physical objects to change whether it is in motion or at rest. Momentum can be more comparable to velocity since it has a direction and a magnitude. Meanwhile, inertia is more about applying resistance to a particular motion in which weight could be included as a factor that could give resistance. In terms of the principle formulated by Isaac Newton, inertia would be the first law of motion while momentum is under the second law of motion.
Momentum takes into account the weight and the velocity of the object. If given a fixed amount of force and velocity, there is no way that the momentum of an object can be stopped unless it is also stopped by an equal force on the other end. This is where inertia comes into play. Inertia delves more into the resistance applied by a particular object whereas the momentum delves more into continuity of motion with regards to mass and velocity. One of the resistances that inertia takes into account would be gravity. The inertia in a particular object is the weight, the force applied to it, and the resistance which is gravity. As force is applied to the object, say a ball, it is more likely to go down as we throw it since there is gravity. Another resistance that inertia considers is friction. We know very well that friction can affect the motion of an object. For example, a truck is speeding in a constant movement of 100 mph. This truck will only be slowed down unless there is friction applied to it which would be the brakes and, of course, the terrain.
In momentum there is such a thing as the preservation of momentum. This implies that the mass and velocity of the moving object is unchanged unless there is force applied to stop it. On the other hand, inertia would rely on the weight of the object whenever it is at rest. If it is in motion, it would consider the resistances aforementioned.
SUMMARY:
1.Momentum is part of classical mechanics while inertia is classical physics.
2.Momentum involves movement while inertia involves resistance to movement.
3.Momentum takes into consideration weight and velocity while inertia considers gravity and friction.
4.Momentum cannot be stopped unless there is applied resistance while inertia can be stopped.