Oh, wow, oh, oh, wow, oh, wow, oh, man.

Oh, wow. Hello and welcome to the Science of Everything podcast, episode 17, energy, work and momentum.

So as you would have gathered from the title of this episode, today we're going to talk about momentum, work and energy.

We're going to, I'm going to divide the podcast into three sections.

First I'll talk about linear momentum, and then I'll move on to angular momentum, momentum in terms of rotation, and finally a section on energy and work.

And this podcast continues on from episode 13 on Newtonian mechanics, so it might be a good

idea to listen to that first if you don't have a basic knowledge of Newtonian mechanics.

Okay, so start off with linear momentum.

What is linear momentum?

Linear momentum is equal to inertial mass times velocity.

So inertial mass, as we spoke about in podcast 13, is essentially the amount of stuff that

something is made of.

It's the mass that contributes to slowing down

of the object when it's, when a force is applied to it, so the greater the inertial mass,

the less it accelerates. So linear momentum is equal to that inertial mass multiplied by

velocity. In fact, you can even restate Newton's first law as, in the form of, in the absence of forces, the momentum of an object remains constant. Remember that the alternative way of stating that Newton's first law is that objects will continue to travel at the same velocity in a straight line until an unbalanced force acts upon them. Well, you can see that if an object is

travelling at the same velocity in a straight line, and obviously its mass is going to be

constant, then its momentum also has to be constant. So, we have this concept, linear momentum,

which is basically mass times velocity. Impulse, by the way, is just the change in momentum, and is equal to the net force that is applied to that object. So you might wonder, why do we have this concept of momentum? Why is it useful? Why would we multiply mass by velocity? The reason is because of the principle of conservation of momentum. And this principle states that the total linear momentum of a system always remains constant.

Always.

So the linear momentum of a particular object stays constant so long as it's not acted on by a force,

but the system as a whole always retains constant linear momentum.

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