Momentum is a vector quantity that represents the product of an object’s mass and its velocity.

In physics, momentum is a fundamental concept that characterizes the motion of an object. It is mathematically defined as the product of an object’s mass $m$ and its velocity $v$. This relationship is often expressed in the formula:

where $p$ denotes momentum. As a vector quantity, momentum possesses both magnitude (size) and direction. Importantly, the direction of the momentum vector aligns with the direction of the velocity vector.

Understanding the interplay between momentum, mass, and velocity is crucial for analyzing the dynamics of moving objects. For instance, an object with a large mass traveling at a slow speed may have the same momentum as a smaller object moving at a higher speed. This equivalence arises because momentum depends on both mass and velocity, rather than either factor in isolation.

Additionally, the concept of momentum is central to the principle of conservation of momentum. This principle asserts that the total momentum of a closed system—one that does not exchange matter or energy with its surroundings—remains constant over time. This holds true regardless of the interactions occurring among the objects within the system. For example, during a collision between two objects, the total momentum before the collision equals the total momentum after the collision, since the momentum lost by one object is gained by the other.

In summary, momentum serves as a measure of an object’s motion, determined by its mass and velocity. As a vector quantity, it shares the same direction as the object’s velocity. Grasping the relationship between momentum, mass, and velocity is essential for understanding various physical phenomena, including collisions and the conservation of momentum.