Final answer:
The slowing of a baseball player due to frictional force while sliding involves the principles of Physics, particularly Newton's second law, demonstrating that momentum is not conserved because of an external force.
Step-by-step explanation:
The scenario of a rightward-moving baseball player slowing to a stop while sliding across the infield dirt applies to Physics, specifically to the concepts of Newton's laws and the conservation of momentum and energy.
When the player stops, it's due to frictional force acting opposite to the movement, converting kinetic energy into thermal energy, as explained in the work-energy theorem.
This process demonstrates Newton's second law of motion: the acceleration of an object is dependent upon two variables - the net force acting upon the object and the mass of the object. Although friction is a non-conservative force, it does work on the player, changing the kinetic energy to other forms.
Hence, the answer is B) Conservation of momentum since in this scenario, momentum is not conserved due to an external force (friction) acting on the system.