Grade 12 · Physics
Momentum
Why it matters
Mass in motion.
Advanced20m readingPrerequisite: None
What is momentum in physics?
Short answer
Momentum is the quantity of motion an object has, equal to its mass times its velocity: p = mv. It is a vector, pointing in the direction of motion, measured in kilogram-metres per second (kg·m/s). In a closed system with no external force, total momentum is conserved, which is why momentum is central to analyzing collisions and explosions.
🔒
This feature is available in the School Plan.
Upgrade to unlock the full lesson, examples, quiz and practice.
Upgrade PlanRelated topics
Frequently asked questions
- Is momentum conserved in every collision?
- Total momentum is conserved in any collision with no external force, whether the collision is elastic or inelastic.
- How is momentum different from kinetic energy?
- Momentum (mv) is a vector and is always conserved; kinetic energy (½mv²) is a scalar and is conserved only in elastic collisions.