Inertia, momentum and impulse

While Physics problems usually explore the interactions between force and motion with a focus on velocity and acceleration, we mustn't forget that mass has an equally significant part to play. 


Key Concepts

Inertia

Heavy bodies require a larger force to get them moving than smaller bodies. They also require more force to make them stop. We say the body has a large inertia (mass), a measure of its reluctance to change velocity.

Momentum

Momentum is defined as the product of a body's mass and velocity.

momentum (p) = mass (m) x velocity (v)

The unit of momentum is a combination of what it is calculated from, usually kg m s-1

The effect that a ball has when it hits a wall depends on its momentum.

Impulse

Impulse is the change of momentum (and, consequently, is the product of force and time) during a collision. This is greater when a ball bounces on a hard floor than when it lands in soft sand.

 

Test Yourself

Use quizzes to practise application of theory.


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Exam-style Questions

Online tutorials to help you solve original problems

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