What is the definition of momentum?

Momentum is defined as the product of an object's mass and its velocity. This relationship can be expressed mathematically as ( p = mv ), where ( p ) represents momentum, ( m ) is mass, and ( v ) is velocity. This definition highlights that momentum is a vector quantity, incorporating both the magnitude (how much) and direction of the object's motion.

Understanding momentum is crucial in physics because it describes the quantity of motion an object possesses. The greater either the mass or velocity of an object, the greater its momentum will be, which is a key concept in analyzing collisions and interactions between objects. The law of conservation of momentum states that in a closed system, the total momentum remains constant, making it a fundamental principle in mechanics.

The other choices, while related to motion in some way, do not accurately define momentum. The sum of all forces relates to Newton's second law and not to momentum directly. Energy in motion pertains to kinetic energy, which is a different concept from momentum. The change in velocity over time describes acceleration, again diverging from the direct definition of momentum itself.