# Relating The Law of Conservation of Momentum to Newton's Third Law of Motion

## Relating The Law of Conservation of Momentum to Newton’s Third Law of Motion

• Newton’s Third Law of Motion states that for every action, there is an equal and opposite reaction. This law can be applied to pairs of forces in a system.

• Momentum is a vector quantity, which means it has both magnitude (size) and direction. It can be calculated using the formula: momentum = mass x velocity.

• The Law of Conservation of Momentum states that in a closed system, the total momentum before an event (such as a collision or explosion) is equal to the total momentum after the event.

• When relating this to Newton’s Third Law, consider an interaction between two objects, like a collision. As the objects collide, they exert equal and opposite forces on each other (Newton’s Third Law), and their velocities change.

• However, the total momentum of the system (the sum of the momentum of each object) remains the same before and after the collision. If one object gains momentum, the other must lose the same amount of momentum for the total to stay the same, illustrating the Law of Conservation of Momentum.

• When solving problems related to momentum and collisions, remember to apply these two principles. Use Newton’s Third Law to understand the forces involved, and the Law of Conservation of Momentum to solve for the changes in velocity of each object.

• In scenarios involving different directions (angles), vector addition and subtraction can be used to calculate total momentum. The direction of momentum can also change, but the total amount of momentum in the system remains constant.

• In real-world applications such as safety features in vehicles and sporting gear, the understanding of these principles is essential, where the aim often is to reduce the force or increase the time over which an impact occurs in order to reduce injury.

• Keep practising problems involving momentum, collisions, and other applications of Newton’s Third Law and the Law of Conservation of Momentum to secure a solid understanding of these principles.

• Remember, the key to mastering Further Motion Concepts is constant practise and understanding the underlying physical principles, not just memorising formulas.