Two equally charged particles separated by 3.20 mm are released from rest. The first particle has an initial acceleration of 7.22 m/s^2 and the second has 9.16 m/s^2. The mass of the first particle is 6.31 × 10^-7 kg. The document determines (a) the mass of the second particle and (b) the magnitude of the common charge. It is found that the mass of the second particle is 4.97 × 10^-7 kg and the common charge is 7.21 × 10^-11 C.