Gravitational Force

Definition

Gravitational force is the attractive force that exists between any two objects with mass. It is the fundamental force responsible for the motion of celestial bodies and the formation of structures in the universe, from planets to galaxies.

5 Must Know Facts For Your Next Test

1. Gravitational force is the force that attracts objects with mass towards each other, and it is the dominant force governing the motion of celestial bodies in the universe.
2. The strength of the gravitational force between two objects is directly proportional to the product of their masses and inversely proportional to the square of the distance between them, as described by Newton's Law of Universal Gravitation.
3. Gravitational force is responsible for the formation of planetary systems, stars, and galaxies, as well as the orbits of these celestial bodies around each other.
4. Gravitational force also plays a crucial role in the expansion and evolution of the universe, as described by the theory of general relativity and the concept of the inflationary universe.
5. The study of the motion of objects under the influence of gravitational forces, known as orbital mechanics, is essential for understanding the dynamics of the solar system and the universe as a whole.

Review Questions

• Explain how the gravitational force is related to the laws of planetary motion.
  • The gravitational force is the fundamental force that governs the motion of planets and other celestial bodies in the solar system. According to Kepler's laws of planetary motion, which were later explained by Newton's Law of Universal Gravitation, the gravitational force between the Sun and the planets is responsible for the elliptical orbits of the planets, the equal areas swept out by the planets in equal times, and the relationship between a planet's orbital period and its distance from the Sun.
• Describe how Newton's Universal Law of Gravitation is used to calculate the gravitational force between two objects.
  • Newton's Universal Law of Gravitation states that the gravitational force between two objects is directly proportional to the product of their masses and inversely proportional to the square of the distance between them. Mathematically, this can be expressed as $F_g = G \frac{m_1 m_2}{r^2}$, where $F_g$ is the gravitational force, $G$ is the gravitational constant, $m_1$ and $m_2$ are the masses of the two objects, and $r$ is the distance between them. This law allows us to calculate the gravitational force between any two objects in the universe, which is essential for understanding the dynamics of orbits and the evolution of celestial bodies.
• Explain how the concept of gravitational force is related to the inflationary universe theory.
  • The inflationary universe theory, proposed as an extension of the Big Bang theory, suggests that the universe underwent a period of rapid expansion in its early stages, driven by a repulsive form of gravitational force. This repulsive gravitational force, known as dark energy, is believed to be a property of space itself and is responsible for the accelerated expansion of the universe observed today. The gravitational force, both attractive and repulsive, plays a crucial role in shaping the large-scale structure of the universe, from the formation of galaxies and clusters to the overall evolution and fate of the cosmos.

Related terms

Newton's Law of Universal Gravitation: The law that states that every particle in the universe attracts every other particle with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.

Orbital Mechanics:

The study of the motion of objects, such as planets and satellites, under the influence of gravitational forces.

Spacetime:

The four-dimensional continuum of space and time in which all physical phenomena, including the gravitational force, are believed to take place.