Kinetic Energy Calculator

Work out the kinetic and gravitational potential energy of a mass, and the speed a fall from a given height would give it.

freeworks offlinenothing uploaded
Input
Output

About kinetic energy calculator

Kinetic Energy Calculator keeps its state in memory and nowhere else. That is why it forgets everything on reload, and why it cannot leak anything.

Load the page once and it works offline from then on. Nothing about the tool needs a connection after that first request.

You will find it under Physics, alongside 6 other tools for the same sort of job.

Runs in this tab, so nothing you type is uploaded.

How to use it

01
Start it
Every control is on the tool itself. Keyboard shortcuts, where there are any, are listed beside it.
02
Watch it run
It updates in the page as you go. Nothing is sent anywhere, so it keeps working with the network off.
03
Close when done
Nothing is stored between visits. Reloading gives you a clean start rather than picking up where you left off.

Examples

2kg moving at 3 m/s, held 5m up
Shows both energy terms and the speed it would hit the ground at from that height
Input
massKg: 2
velocityMetresPerSecond: 3
heightMetres: 5
Output
Kinetic energy joules: 9
Potential energy joules: 98.066
Drop speed metres per second: 9.903
Drop speed kmh: 35.65

Questions

Does Kinetic Energy Calculator work offline?+

Yes. It is JavaScript running in this tab, so once the page has loaded it needs nothing further from the network. Put the machine in flight mode and it carries on. Nothing you do here is sent anywhere, because there is nowhere for it to go.

Does it remember anything between visits?+

No. Reload the page and it starts from nothing. There is no account, no saved state and no cookie holding your last session. That is a deliberate trade: it cannot lose your data because it never keeps any.

Is it accurate?+

Timing comes from performance.now(), the high resolution clock the browser provides, rather than from setInterval, which drifts by a few milliseconds every tick and compounds over minutes. What can still shift things is the browser throttling a tab in the background, so leave it visible if the timing matters.

Does it make a sound?+

Where a sound makes sense, it is generated with the Web Audio API rather than loaded as a file, so there is nothing to download and nothing to block. Browsers refuse to start audio until you have interacted with the page, which is why the first press is what switches it on.

Can I use Kinetic Energy Calculator on a phone?+

Yes. The controls are sized for touch and the layout collapses to one column on a narrow screen. Bear in mind that a phone locking its screen will suspend the page, and timing stops with it.