A lovely puzzle (Galperin): Why do colliding blocks compute π?
 

Formulation:
[YOUTUBE]HEfHFsfGXjs[/YOUTUBE]

Solution:
[YOUTUBE]jsYwFizhncE[/YOUTUBE]

:tu:

Nice graphics. Good speaker. Interesting problem.

[size=1]Whenever I see pi involved I know there is a way to make a circle somehow in the calculations. Let me think about it.[/size]

[QUOTE=Batalov;536156]Formulation:
[YOUTUBE]HEfHFsfGXjs[/YOUTUBE]

Solution:
[YOUTUBE]jsYwFizhncE[/YOUTUBE][/QUOTE]

3rd movie in that series is also beautiful:

[YOUTUBE]brU5yLm9DZM[/YOUTUBE]

All of the videos from 3Blue1Brown has these nice graphics.

His series on linear algebra explains it so intuitively with the graphics. It should be taught this way in school:

[url]https://www.youtube.com/watch?v=fNk_zzaMoSs&list=PLZHQObOWTQDPD3MizzM2xVFitgF8hE_ab[/url]


He also have a series on calculus I have not watched yet:

[url]https://www.youtube.com/watch?v=WUvTyaaNkzM&list=PLZHQObOWTQDMsr9K-rj53DwVRMYO3t5Yr[/url]

[QUOTE=retina;536160][size=1]Whenever I see pi involved I know there is a way to make a circle somehow in the calculations. Let me think about it.[/size][/QUOTE]

[quote]De Morgan was explaining to an actuary what was the chance that a certain proportion of some group of people would at the end of a given time be alive; and quoted the actuarial formula, involving [tex]\pi[/tex], which, in answer to a question, he explained stood for the ratio of the circumference of a circle to its diameter. His acquaintance, who had so far listened to the explanation with interest, interrupted him and exclaimed, "My dear friend, that must be a delusion, what can a circle have to do with the number of people alive at a given time?"[/quote]
-- W.W. Rouse Ball, [u]Mathematical Recreations and Essays[/u]