Actueel
Archief
Culinair
Didactiek
Documentatie
Etalage
Formules
Fotoboeken
Functies
Geschiedenis
ICT
ICTauteur
Laatste nieuws
Lesmateriaal
Muziek
Natuur
Onderwijs
Ontspanning
Persoonlijk
Probleemaanpak
Proeftuin
Puzzels
Rekenen
Rekenmachines
Ruimtemeetkunde
Schoolwiskunde
Snippers
Systeem
Taal van de wiskunde
Vergelijkingen
Verhalen
WisFaq
WisKast




Oplossing week 31

Four. “Generally speaking, when a body rotates round a circle, it always does one revolution more than one can count. It is precisely this that explains why the earth, revolving round the sun, succeeds in rotating on its axis not in 365 1/4 days, but in 366 1/4 days, if one counts its revolutions in respect to the stars and not the sun. You will understand now why sidereal days are shorter than solar days.”

From Perelman’s Figures for Fun, 195

©2004-2024 W.v.Ravenstein