Like searched the internet and everyone is saying that it is an energy due to speed or something but like I don’t get it. How can something like kinetic energy exists if there is no such thing as speed( I think like speed is no such thing as gravitation or nuclear speed is something else it is not similar like nuclear or gravity)
In: Physics
Kinetic energy derives from velocity. Velocity is a change of position over time, with a particular direction. E.g. if you walk two meters east, over one second, that would be a velocity.
Velocity, usually denoted “v”, measures how displacement (position where you care about direction) changes over time. Kinetic energy, by definition, is equal to 1/2×m×v^2 and represents the amount of energy “stored” in the motion of that object. Another way you could think of it is: How much energy, aka “work,” would you have to do, in order to make that moving object come to a complete standstill. The kinetic energy of a body is that energy.
We actually use kinetic energy as a storage medium in real life, too! Specifically in devices called flywheels. You can spin up a flywheel so that it’s going really, really, *really* fast, and then use that spinning speed to power other devices. That slows the wheel down, until eventually it runs out of rotational kinetic energy, coming to a stop. They are used in places that need smaller energy storage and don’t mind the occasional spin-up or replacement.
Pendulums and springs are other examples of systems that alternate between kinetic energy and potential energy. When a spring is compressed, it has a lot of elastic potential energy stored in it. If you attach a spring to the ceiling, stick a weight on the end, and let it bounce, it will oscillate back and forth, changing between having the spring compressed or stretched (=elastic potential energy) and having the weight moving downward or upward with the spring (=kinetic energy). Note that, even though velocity can be negative, kinetic energy cannot, because you square the velocity term, and thus remove any negative sign it might have.
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