A heavy nucleus N, at rest, undergoes fission N → P + Q, where P and Q are two lighter nuclei. Let δ = Mₙ − Mₚ − Mq, where Mₚ, Mq and Mₙ are the masses of P, Q and N, respectively. Eₚ and Eq are the kinetic energies of P and Q, respectively. The speeds of P and Q are vₚ and vq, respectively. If c is the speed of light, which of the following statement(s) is(are) correct?