Everyday barn pole paradox problems come down to one relationship between 5 figures. This calculator takes length of the barn (l), speed of light in the vacuum, length of the pole (l), speed (v), front of the pole enters and turns them into front of the pole leaves and back of the pole enters, with the working shown so you can check the result rather than simply trust it.
What Is the Barn Pole Paradox Calculator?
It is built around front of the pole leaves, back of the pole enters, back of the pole leaves, and it works the same way whether you are checking a homework answer, confirming a colleague's figure, or working something out for yourself. Everything runs in your browser, so nothing you enter is uploaded anywhere.
How the Barn Pole Paradox Calculation Works
The steps are applied in order, so an output that depends on another output updates as soon as the underlying figures change.
The relationship between length of the barn (l), speed of light in the vacuum, length of the pole (l), speed (v), front of the pole enters and front of the pole leaves, back of the pole enters, back of the pole leaves, front of the pole leaves, front of the pole enters, back of the pole enters, back of the pole leaves, contracted pole length, contracted barn length, lorentz parameter (γ), both doors closed, front door closes, back door closes, speed ratio (ß) is fixed, so the same figures always give the same answer. That makes it a good cross-check: run the numbers a second way and see whether the result agrees.
Getting a Result You Can Trust
For anything that matters, write the inputs down next to the result. A calculation you can reproduce is worth far more than a number you cannot explain, and it takes a moment to record length of the barn (l) and speed of light in the vacuum and length of the pole (l) and speed (v) and front of the pole enters alongside front of the pole leaves, back of the pole enters, back of the pole leaves.
Frequently Asked Questions
What do I need to work out front of the pole leaves?
Enter length of the barn (l), speed of light in the vacuum, length of the pole (l), speed (v), front of the pole enters. The calculator then works through the relationship and reports front of the pole leaves, back of the pole enters, back of the pole leaves.
What does the barn pole paradox actually calculate?
It takes length of the barn (l) and speed of light in the vacuum and length of the pole (l) and speed (v) and front of the pole enters and converts them into front of the pole leaves, back of the pole enters, back of the pole leaves using the standard relationship for this problem. Each step is applied in turn, so every output is traceable back to the numbers you typed in.
How should I enter length of the barn (l)?
Use the value you actually have, in the unit shown next to the field. Enter every value in the same unit system. The calculator assumes the figures you supply are consistent, so it cannot correct a mistake that happens before the calculation starts.
Why does a small change in one value move the answer so much?
That happens when an output depends on a ratio, because dividing by a small number magnifies any change in it. Check the units first, then check whether the value you entered is in the range the relationship was designed for.
Can I use this for a quick estimate as well as a precise answer?
Yes. The calculator is built for quick checks, so round your inputs to a sensible number of significant figures and the result will be just as useful. If you need more precision, keep the same method and add digits to the inputs rather than adjusting the method itself.