Gravitational force

Definition

Gravitational force is the attractive force that exists between any two masses, drawing them toward each other. This fundamental force is crucial for understanding how objects interact in motion and the behavior of objects in relation to surfaces, affecting everything from falling objects to the orbits of celestial bodies.

5 Must Know Facts For Your Next Test

1. Gravitational force decreases with increasing distance between two masses, following an inverse square relationship.
2. On Earth, gravitational force gives weight to objects and is approximately 9.81 m/s², which is the acceleration due to gravity.
3. Gravity is not just a force on Earth; it acts between all masses in the universe, influencing everything from apples falling to planets orbiting stars.
4. The gravitational force is responsible for keeping the planets in orbit around the Sun and maintaining the Moon's orbit around Earth.
5. When an object is in free fall, it experiences gravitational force but no other forces like friction or air resistance, leading to a constant acceleration toward the Earth.

Review Questions

• How does gravitational force relate to Newton's laws of motion, particularly in terms of how it affects an object's state of rest or motion?
  • Gravitational force plays a significant role in Newton's laws of motion by influencing how objects behave when at rest or in motion. According to Newton's first law, an object will remain at rest or continue in uniform motion unless acted upon by a net external force. Gravitational force acts as a constant pull on all objects near Earth, determining their weight and affecting their motion when they are dropped or thrown. This interaction is also essential for understanding how different forces, like friction and gravitational force, work together to affect an object's overall motion.
• Discuss how gravitational force impacts the concept of weight and how this relationship varies in different locations.
  • Gravitational force directly affects weight, which is defined as the gravitational pull acting on an object's mass. Weight can be calculated using the formula $$W = mg$$, where $$g$$ varies based on location due to differences in gravitational pull. For example, weight is less on the Moon than on Earth because the Moon has less mass and thus exerts a weaker gravitational force. Understanding this relationship helps clarify why astronauts experience weightlessness during free fall while orbiting Earth despite being under the influence of gravity.
• Evaluate how gravitational force influences both terrestrial and astronomical phenomena and discuss its implications for our understanding of the universe.
  • Gravitational force is crucial in both terrestrial and astronomical contexts; it governs the motion of falling objects on Earth and dictates the orbits of planets, stars, and galaxies. On Earth, gravitational force causes objects to fall towards the ground and determines their weight. In contrast, at an astronomical level, gravity shapes the structure of the universe by influencing the formation of galaxies and the movement of celestial bodies. The interplay between gravitational forces not only leads to predictable patterns in motion but also deepens our understanding of cosmic phenomena such as black holes and gravitational waves.

Related terms

Newton's Law of Universal Gravitation: A law that states every point mass attracts every other point 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.

Weight: The force exerted by gravity on an object, calculated as the product of its mass and the acceleration due to gravity, commonly represented as $$W = mg$$.

Free Fall: The motion of an object falling solely under the influence of gravity, experiencing no other forces like air resistance.