Collisions and the conservation of linear momentum

Section 1: Understanding Collisions

Comprehend that a collision refers to an event where two or more bodies exert forces on each other for a relatively short period.
Understand different types of collisions: elastic collisions, where kinetic energy is conserved, and inelastic collisions, where kinetic energy is not conserved.
Be aware that perfectly inelastic collisions are a subset of inelastic collisions, where the objects stick together and move as one after the collision.

Section 2: Conservation of Momentum

Grasp the principle of Conservation of Momentum, which states that the total linear momentum of a closed system remains constant, before and after a collision.
Know how to calculate the momentum of an object using the formula: momentum = mass x velocity.
Understand that while individual momenta of bodies involved in a collision can change, their total momentum remains the same.

Section 3: Coefficient of Restitution

Learn about the Coefficient of Restitution (e), which is a measure of the elasticity of a collision.
Remember the formula e = (relative speed after collision) / (relative speed before collision), and understand that it ranges from 0 to 1, with 1 indicating a perfectly elastic collision and 0 a perfectly inelastic collision.

Section 4: Solving Collision Problems

Familiarise with the method of imparting momentum, which involves applying an impulse (force multiplied by time) to change an object’s velocity and therefore its momentum.
Practise constructing free-body diagrams to understand the forces at play during a collision.
Learn how to use simultaneous equations to solve problems involving conservation of momentum and coefficient of restitution.
Be comfortable with some concepts of vectors, as the velocity and forces can have both magnitude and direction.
Make sure to solve plenty of past paper questions to test your understanding of the topic and improve your problem-solving skills.