Impulse

Table of Contents

Impulse

Impulse is when a force is applied, changing the acceleration, which changes the velocity, which changes the momentum.

Formulas

$\overrightarrow{J}=△\overrightarrow{p}={\overrightarrow{p}}_{final}-{\overrightarrow{p}}_{initial}$ $\overrightarrow{J}=F_{net}(△t)$

SI Units

• $Ns$ newton seconds
• $\frac{kgm}{s}$

Softened Impact

Egg

A egg breaks on the ground, but an egg on a sheet does not break because, the force is applied over a longer period. $\overrightarrow{J}$ is constant. $△t$ increases $\uparrow$ thus, $\overrightarrow{F}$ decreases $\downarrow$

Car collisions

A collision softened on many fronts

• Front of car crumbles so people are slowed down
• Helmets reduce average force on the head. Increases time for head to come to stop
• Airbag provides small force to slow you down, applied over a longer time