Kuenzana pakati pehuwandu nesimba, sekutaurwa ne formula E = mc2, ndiyo mhedzisiro yakakurumbira ye special relativity. Mu relativity, huwandu nesimba inzira mbiri dzakasiyana dzekurondedzera huwandu hwepanyama. Kana hurongwa hwepanyama hune simba, hunoitawo huwandu hunoenderana, uye zvinopesana. Kunyanya, zvivakwa zvese zvemuviri zvine chekuita nesimba, senge tembiricha yayo kana kusunga masisitimu esimba senge nyukireya kana mamorekuru, zvinopa huwandu hwemuviri iwoyo, uye nekudaro zvinoshanda se masosi egiravhiti. Mu special relativity, simba rakabatana zvakanyanya ne momentum. Sezvakangoita nzvimbo nenguva, mune iyo dzidziso, mativi akasiyana echinhu chakazara chinonzi nzvimbo-nguva uye simba ingori mativi akasiyana eakabatana, mana-mativi akaenzana ayo ma physicists anodaidza mana-momentum. Mu relativity, kana hurongwa hwepanyama hune simba, zvakare ine huwandu hunoenderana, uye zvinopesana.
uremu, simba, kufamba, kumanikidza uye kumanikidza