Doppler Effect

$f_{\text{obs}}=f_{\text{source}}\left(\frac{v_{\text{sound}}+v_{\text{obs}}}{v_{\text{sound}}+v_{\text{source}}}\right)$

• Observer to source is positive
• $v_{\text{sound}}=\text{343}\frac{m}{s}$

Mnemonic

• OS is alphabetical, so it O to S is positive and velocity of observer over velocity of source