The correct option is **A. Electrostatic forces can be both attractive and repulsive, while gravitational forces are always attractive.** ### Detailed Explanation 1. **Understanding Electrostatic Forces:** - Electrostatic forces arise from the interaction between charged particles. There are two types of charges: positive and negative. - When two like charges (both positive or both negative) are brought close together, they repel each other. Conversely, when a positive charge and a negative charge are near each other, they attract each other. - This dual nature (both attractive and repulsive) is a fundamental characteristic of electrostatic forces. 2. **Understanding Gravitational Forces:** - Gravitational forces, on the other hand, are always attractive. They arise from the mass of objects and the gravitational interaction between them. - No matter the situation, two masses will always attract each other. This is described by Newton's law of universal gravitation, which states that every mass attracts every other mass with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centers. 3. **Comparison of Forces:** - The key difference highlighted in option A is crucial: electrostatic forces can either attract or repel, while gravitational forces can only attract. This difference leads to various implications in physics, such as the stability of atomic structures (where electrostatic forces play a significant role) and the behavior of celestial bodies (where gravitational forces dominate). ### Why Other Options Are Incorrect **B. Electrostatic forces are significantly weaker than gravitational forces at all distances.** - This statement is incorrect. While gravitational forces are indeed very weak compared to electrostatic forces at small distances, electrostatic forces can be much stronger than gravitational forces at the atomic and molecular levels. For example, the electrostatic force between two electrons is significantly stronger than the gravitational force between them. **C. Gravitational forces can act on charged objects, while electrostatic forces can only act on neutral objects.** - This statement is misleading. Gravitational forces act on all masses, regardless of whether they are charged or neutral. Electrostatic forces, however, specifically act on charged objects. Neutral objects can experience electrostatic forces only if they are polarized in the presence of a charged object, but they do not have their own electrostatic force. **D. Electrostatic forces act over much longer ranges than gravitational forces.** - This statement is also incorrect. In fact, gravitational forces act over much longer ranges than electrostatic forces. While both forces can act over large distances, the strength of electrostatic forces diminishes rapidly with distance (following an inverse square law), while gravitational forces, although weak, can still be significant over astronomical distances. ### Summary of Key Points - **Electrostatic forces** can be both attractive and repulsive, depending on the nature of the charges involved. - **Gravitational forces** are always attractive and act between masses. - The strength of electrostatic forces can be much greater than gravitational forces at small distances. - Gravitational forces act on all masses, while electrostatic forces specifically act on charged objects. This understanding of the differences between electrostatic and gravitational forces is fundamental in physics and helps explain a wide range of phenomena, from atomic interactions to the motion of planets.