A stationary particle breaks into two parts of masses \( m_A \) and \( m_B \) which move with velocities \( v_A \) and \( v_B \) respectively. The ratio of their kinetic energies \( (K_B : K_A) \) is:
\( m_B v_B : m_A v_A \)
\( m_B : m_A \)
\( 1 : 1 \)
\( v_B : v_A \)