Problems in Physics

Hey, I want to say that I like the idea! But honestly, I never used physics in practice. My experience with physics was in school, and a lot of years passed since then...

Tested the site and it actually works. Great job!

I even solved the first task, but for others I need to restore my physics skills :).

I solved the second task on the physics site (pretty advanced for my level, by the way), and started solving the third one.

It seems that I found the correct formula (at least it gives the same answer as in example), but on submission I get:

Expected answer was:

okko

I do not understand what okko means.

I tried to post a question on the new site's forum, but got:

Page not found

Excuse us, but there is no such page.

So I'm posting my question here.

And fourth task did not worked for me as well.

I tested my formula with the following program:

from math import atan, cos
V = 40
W = 30
T = 20
print(V * T / (V * cos(atan(W / V))))

Output is 25.0

But checker disagrees:

Expected answer was:

Wrong result for V=40, W=30, T=20 - should be about 25.000 but got 33.525913620569

Seems that I was hasty with the conclusion that site actually works. Yes, it works, but there is still a lot of problems to address...

Hi Rodion!

The site of Physics problems is very cool!! The "formula-input" style feels very fitting for the subject, and it's a perfect example of tweaks that could be made to the basic framework to give the new product a unique personality. You've set it up nicely so that someone following along is invited to think "what other unique things could I do with these tools"? I'm amazed with the speed with which you've designed and launched it!

I recall many long nights in school working through formula-based problems like these - no actual numbers, just equation manipulation. I look forward to re-living those good old days :)

I mentioned in an email a while back I was thinking about making some problems geared more towards learning some real-world concepts in Math and Engineering, and this is a huge inspiration to get moving on those. There's so many interesting concepts that are used in real-life day-to-day applications that aren't often discussed, despite having entire Wikipedia pages dedicated to them.

To Rodion: I must say that I'm impressed with the speed you fixed the problems mentioned above. I thought it will take a long time to debug and handle these issues. Very cool!

To moxieman: I'm very impressed by simplicity of your solution for "When stones fall". My solution is five times longer, and obviously I am overcomplicating things as always. Where can I read about your approach?

Hi qwerty! I'd recommend taking a look at Newton's laws of motion. Essentially you can take F = m*a and apply calculus to derive all the equations that you need. But almost everybody who starts learning this does so before they learn calculus, so they are usually provided the already-derived equations.

While they are still presented in "calculus-form" on that Wikipedia page, the equations in the "Prerequisites" section are essentially those already-derived equations. With some clever rearranging and substitution, you should be able to end up with my solution.

And there's certainly nothing wrong with your solution - just a different approach that ends up at the same goal!

Thanks, moxieman! I will try to think about it.

Hi Rodion,

I've just complete Alferov's Peace - Problem 12 (Center of mass) and the checker says "okko" as expected answer. Could you please check it? Thanks in advance!

Thanks for the fix! Although I have much less knowledge in physics than in math I really enjoy these type of problems too :) Thank you!