Gravitational Force

Definition

Gravitational force is the attractive force that exists between any two objects with mass. It is the force that keeps planets in orbit around the sun and causes objects to accelerate towards the Earth's surface at a constant rate known as the acceleration due to gravity.

5 Must Know Facts For Your Next Test

1. 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.
2. Gravitational force is the dominant force governing the motion of celestial bodies, such as planets, moons, and stars, in the universe.
3. The acceleration due to gravity on the Earth's surface is approximately 9.8 m/s^2, meaning that objects near the Earth's surface will accelerate downward at this rate.
4. Gravitational potential energy is the potential energy an object possesses due to its position in a gravitational field, and it is converted to kinetic energy as the object falls.
5. Tidal forces, which are differences in gravitational pull across an object, can cause deformation and heating, as seen in the case of the Earth's tides and the internal heating of Jupiter's moon Io.

Review Questions

• Explain how the gravitational force between two objects is calculated using Newton's Law of Universal Gravitation.
  • According to Newton's Law of Universal Gravitation, 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. The formula for this relationship is: $F_g = G \frac{m_1 m_2}{r^2}$, where $F_g$ is the gravitational force, $G$ is the gravitational constant (approximately 6.67 × 10^-11 N⋅m^2/kg^2), $m_1$ and $m_2$ are the masses of the two objects, and $r$ is the distance between their centers.
• Describe how the acceleration due to gravity affects the motion of objects in the context of 3.4 Motion in Space.
  • The acceleration due to gravity, denoted as $g$, is a constant that governs the motion of objects in the Earth's gravitational field. In the context of 3.4 Motion in Space, the acceleration due to gravity plays a crucial role in the trajectories and orbits of objects, such as satellites, rockets, and celestial bodies. For example, the acceleration due to gravity keeps satellites in stable orbits around the Earth, and it determines the launch velocities required for spacecraft to escape the Earth's gravitational pull and travel to other destinations in the solar system.
• Analyze how the concept of gravitational potential energy is related to the motion of objects in 3.4 Motion in Space.
  • Gravitational potential energy is the potential energy an object possesses due to its position in a gravitational field. In the context of 3.4 Motion in Space, gravitational potential energy is a key factor in the motion of objects, as it is converted to kinetic energy as the object falls or moves through the gravitational field. For example, a satellite in a higher orbit has more gravitational potential energy than a satellite in a lower orbit, and as the satellite loses altitude, its gravitational potential energy is converted to kinetic energy, allowing it to maintain its orbital velocity. Understanding the relationship between gravitational potential energy and kinetic energy is crucial for analyzing and predicting the motion of objects in space.

Related terms

Newton's Law of Universal Gravitation: The principle that any two objects with mass exert a gravitational force on each other, with the force being directly proportional to the masses of the objects and inversely proportional to the square of the distance between them.

Gravitational Potential Energy: The potential energy an object possesses due to its position in a gravitational field, which is directly proportional to the mass of the object and its height above the Earth's surface.

Acceleration Due to Gravity: The constant rate at which an object accelerates towards the Earth's surface due to the Earth's gravitational pull, typically denoted as 'g' and having a value of approximately 9.8 m/s^2.