* Inertia is the tendency of an object to resist changes in its motion. It's directly related to an object's mass.

* Momentum is a measure of an object's motion. It depends on both the object's mass and its velocity.

Example:

Imagine two cars:

* Car A: Heavy truck, stationary (velocity = 0)

* Car B: Small car, moving at a moderate speed

Both cars have the same inertia (mass), but Car B has momentum because it's moving. Car A has no momentum because it's stationary.

In summary:

* Two objects can have the same inertia (mass) but different momentum if they have different velocities.

* If two objects have the same mass and the same velocity, they will have the same momentum.