Final answer:
In an endoergic reaction where a projectile bombards a stationary nucleus, momentum is conserved. While kinetic energy may not be, mass-energy conservation is crucial. Momentum conservation is a fundamental law applicable to all closed systems without external forces.
Step-by-step explanation:
The question posed deals with the principle that during endoergic nuclear reactions, where a projectile bombards a stationary nucleus, momentum is conserved. It is important to understand that in physics, the conservation of momentum is a fundamental law that applies to all systems, including nuclear interactions. Whether it is an explosion, decay, or collision, the total momentum of a closed system will not change. For example, when a nucleus undergoes radioactive decay while at rest, the resulting fragments must have equal and opposite momentum such that the system's overall momentum remains zero.
In the case of a bombarding projectile, the initial momentum of the projectile will equal the final momentum of the products. Since no outside forces are acting on the system, momentum conservation applies. However, the kinetic energy is not necessarily conserved in such reactions. In nuclear reactions, conservation of mass-energy is also crucial, as described by E=mc². Although the mass of reactants can change due to the conversion of mass to energy, the conservation of total mass-energy and the number of nucleons ensure that nuclear reactions adhere to conservation principles.