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# Momentum

How to keep things moving.

# A preview of "Momentum"Join Brilliant Premium

We are surrounded by objects in motion like cars, airplanes, meteors, planets, and air molecules.

In these quizzes, we will consider two quantities: impulse and momentum. Momentum is a measure of motion for an object, while impulse is a measure of changes in motion - which is equivalent to the total change in momentum.

By the end, you’ll have a deep understanding of their relationship and implications - and we’ll even do some investigation of $$E=mc^2.$$

The relationship given by the impulse-momentum theorem allows us to explain everyday phenomena.

When people or other kinds of animals fall from high places, they'll usually bend their legs (and arms) upon landing. This behavior is intuitive, but why is it done?

In short, during a fall, an animal can increase the time of impact $$\Delta t$$ by bending their legs. This reduces the force of impact and therefore increases the chance that bones will withstand the deceleration.

By the end of these quizzes, you’ll be exposed to mass-energy equivalence - one of the deepest relations in physics that implies that energy and mass are equivalent.

Light has long been known to carry energy, but less well known is its intrinsic momentum. Perhaps the most universally recognized equation in all of science is the mass-energy equivalence relation, given by $$E = mc^2.$$

It turns out that this relation can be obtained through modest means, and in these quizzes, we’ll do a thought experiment (or gedanken) using the setup shown below to explain it:

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