If the uranium nucleus is at rest before its decay, which one of the following statements is true concerning the final nuclei?
A)They have equal kinetic energies, but the thorium nucleus has much more momentum.
B)They have momenta of equal magnitudes, but the thorium nucleus has much more kinetic energy.
C)They have equal kinetic energies and momenta of equal magnitudes.
D)They have equal kinetic energies, but X has much more momentum.
E)They have momenta of equal magnitudes, but X has much more kinetic energy.

Question

Quizplus · Accepted Answer

Due to conservation of momentum, the final nuclei have momenta of equal magnitudes. However, because kinetic energy depends on both mass and velocity, the lighter nucleus (X) will have more kinetic energy.

If the Uranium Nucleus Is at Rest Before Its Decay