Momentum and Impulse (AS)

The principle of conservation of momentum states that total momentum remains constant before and after a collision if no external forces are acted on the objects involved.
Momentum is a vector quantity and in any problem regarding momentum, both the magnitude and the direction should be considered.
The momenta of any two objects before a collision can be calculated by summing their individual momenta (product of each one’s mass and velocity).
An elastic collision is one in which the total kinetic energy before the collision is equal to the total kinetic energy after the collision. In this type of collision, both energy and momentum are conserved.
In an inelastic collision, the total kinetic energy is not the same before and after the collision. However, momentum is still conserved.
momentum is always conserved during explosions where an object splits into two or more particles.
The impulse of a force is the product of the force and the time during which it acts and is equal to the change in the momentum of an object.
The impulse-momentum theorem states that the impulse on an object is equal to the change in its momentum.
Modelling an object as a particle can simplify problems in mechanics but can be revised into more complex models if the particle approximation is not valid.
Understanding how to draw and interpret force-time graphs is important as they can provide information about the impulse delivered to an object.
Worked examples and practise problems are a key part of understanding the concepts behind momentum and impulse- ensure to use them as a major way to revise.
Look beyond merely memorising definitions and equations; understanding their practical applications and being able to apply them to solve problems is crucial.