Energy is the ability to do Work.
That’s what ur mum says too, so it must be true. Eat your green vegetables.
But there’s a lot of ways for work to be done, so it’s a lil bit more complicated than that.
The Wikipedia says: “energy is the property that must be transferred to an object in order to perform work on – or to heat – the object, and can be converted in form, but not be created or destroyed.” – which makes sense, but what exactly does this tell us?
Tells us that Energy is a pretty abstract concept – it’s a “property” like Inertia is. Also tells us that there are a lot of different forms of energy. For instance, there’s Mechanical Energy which is the sum of an object’s macroscopic Kinetic and Potential energies (the former being a function of an object’s velocity, the latter being a function of the object’s position in a Force Field), there’s the Chemical Energy stored in the molecules all around you. There’s tons – the following table kinda gives an overview of some of the more well known types.
|Type of energy||Description|
|Kinetic||(≥0), that of the motion of a body|
|Potential||that stored by an object’s position in a force field (comprises many of the forms below)|
|Mechanical||the sum of (usually macroscopic) kinetic and potential energies|
|Electric||that from electric fields|
|Magnetic||that from magnetic fields|
|Gravitational||that from gravitational fields|
|Chemical||that of chemical bonds (and chemical reactions)|
|Ionization||that of binding an electron to its atom or molecule|
|Nuclear||that of binding nucleons to form the atomic nucleus (and nuclear reactions)|
|Chromodynamic||that of binding quarks to form hadrons|
|Elastic||that of deformation of a material (or its container) exhibiting a restorative force|
|Mechanical wave||(≥0), that propagated by a deformational wave through an elastic material|
|Sound wave||(≥0), that propagated by a sound wave, a form of mechanical wave|
|Radiant||(≥0), that propagated by electromagnetic radiation, including light|
|Rest||(≥0) that equivalent to an object’s rest mass|
|Thermal||a microscopic, disordered equivalent of mechanical energy|
As you can see, I poached this off the Wikipedia – I recommend checking it out.
What good does all this do?
Well, there are a few pretty useful results in physics, such as The Conservation of Energy (from tons of physicists pre-1900’s, that recognized energy lost from motion (Friction) is converted to Heat) and Mass-Energy Equivalence (from Einstein).
Knowing these principles can be pretty gd useful when you’re solving – what is essentially – a math problem that just happens to describe a physical system/situation/scenario. There’s a lot of pretty complicated maths and ideas I know of, but as of yet can’t say I understand entirely (if at all) – all I can do now is point to their Wiki’s and wish youse the best of luck (I need it too). It’s called Hamiltonian Mechanics and it’s pretty wicked, having to do with maths I’ve only read about in books (Calculus of Variations)
Catch ya on the flip side!