Key Definitions
- Gravity: A force of attraction between any two objects with mass.
- Mass: The amount of matter in an object.
- Weight: The force of gravity acting on an object.
- Gravitational Field: A region of space around a massive object where another object experiences a gravitational force.
Key Formulas
-
Newton's Law of Universal Gravitation:
- F = G * (m1 * m2) / r^2
- Where:
- F is the gravitational force between two objects
- G is the gravitational constant
(approximately 6.67 x 10^-11 Nm^2/kg^2) - m1 and m2 are the masses of the two objects
- r is the distance between the centers of the two objects
-
Gravitational Potential Energy:
- U = -G * (m1 * m2) / r
- Where:
- U is the gravitational potential energy of the system
- G, m1, m2, and r are the same as in Newton's Law
Key Concepts
- Gravitational acceleration: The acceleration due to gravity near the surface of a planet or other celestial body. On Earth, it is approximately 9.81 m/s^2.
- Orbit: The path followed by an object that is moving around another object under the influence of gravity.
- Escape velocity: The minimum speed required for an object to escape the gravitational pull of a planet or other celestial body.
Examples
- The Moon orbiting the Earth: The Moon is held in orbit around the Earth by the gravitational force between them.
- Falling objects: Objects fall to the ground due to the gravitational force of the Earth.
- Artificial satellites: Satellites orbit the Earth at a specific altitude to avoid atmospheric drag and maintain a stable orbit.
Additional Notes
- The gravitational force between two objects is always attractive, regardless of their masses or charges.
- The gravitational force between two objects decreases as the distance between them increases.
- The gravitational potential energy of a system is negative, indicating that work must be done to separate the objects.
