Summary
Momentum is the product of an object's mass and its velocity, and it is a vector quantity, meaning it has both magnitude and direction. The principle of conservation of momentum states that in a closed system, the total momentum before and after a collision remains constant, provided no external forces act.
- Momentum — mass of the body multiplied by its velocity Example: A car with a mass of 1000 kg moving at 20 m/s has a momentum of 20,000 kg m/s.
- Impulse — change of momentum Example: When a force acts on a car for a certain time, it changes the car's momentum.
- Principle of Conservation of Momentum — total momentum before collision equals total momentum after collision Example: Two ice skaters push off each other and move in opposite directions with equal and opposite momentum.
Exam Tips
Key Definitions to Remember
- Momentum is mass times velocity.
- Impulse is the change in momentum.
- Conservation of momentum states that total momentum is constant in a closed system.
Common Confusions
- Confusing momentum with force.
- Forgetting that momentum is a vector and can be negative.
Typical Exam Questions
- What is momentum? Momentum is the product of mass and velocity.
- How is impulse related to momentum? Impulse is the change in momentum.
- What happens to momentum in a collision? Total momentum is conserved.
What Examiners Usually Test
- Understanding of momentum as a vector quantity.
- Application of the conservation of momentum in collision problems.
