Electric Potential Energy: Practice Problem & Solution

Solution Explained:

To solve this problem, we apply the core principles of Electric Potential Energy. Understanding the underlying formula is key to arriving at the correct answer below:

For a free target, kinetic energy is shared, reducing the effective kinetic energy, leading to a larger closest approach distance (A is true). For a free target, mechanical energy of interacting particles is conserved. For a fixed target, external forces do work, so mechanical energy of the interacting particles is not conserved (R is true). This difference explains (A).