What phrase best describes forces that are always attractive and depend on mass and distance?

What phrase best describes forces that are always attractive and depend on mass and distance?

• A. Gravitational forces
• B. Magnetic forces
• C. Electric forces
• D. Nuclear forces

Answer: (A)

Gravity is the force that always pulls masses toward each other, and its strength grows with bigger masses and shrinks as the distance between them grows. Newton’s universal law says the force is proportional to the product of the two masses and inversely proportional to the square of the distance between them. So larger masses pull harder, and the pull weakens quickly as they move apart. The direction is along the line joining the two masses, always toward one another. This isn’t the same for electric or magnetic forces, which can attract or repel depending on the signs of charges or the orientation of magnetic poles, and nuclear forces act only at very short ranges within nuclei and don’t follow the simple mass-distance pattern. A classic example is the Sun and Earth: gravity draws Earth toward the Sun, binding the orbit, with the force diminishing as distance increases but never turning into repulsion.

Gravity is the force that always pulls masses toward each other, and its strength grows with bigger masses and shrinks as the distance between them grows. Newton’s universal law says the force is proportional to the product of the two masses and inversely proportional to the square of the distance between them. So larger masses pull harder, and the pull weakens quickly as they move apart. The direction is along the line joining the two masses, always toward one another.

This isn’t the same for electric or magnetic forces, which can attract or repel depending on the signs of charges or the orientation of magnetic poles, and nuclear forces act only at very short ranges within nuclei and don’t follow the simple mass-distance pattern. A classic example is the Sun and Earth: gravity draws Earth toward the Sun, binding the orbit, with the force diminishing as distance increases but never turning into repulsion.