key term - Newton’s first law

Definition

Newton's first law, also known as the law of inertia, states that an object at rest will stay at rest, and an object in motion will stay in motion with the same speed and direction unless acted upon by an external force. This principle explains why celestial bodies remain in their orbits absent significant external influences.

5 Must Know Facts For Your Next Test

1. Newton’s first law is fundamental to understanding why planets continue to orbit the sun without deviating from their paths.
2. The concept of inertia is central to Newton’s first law; it explains resistance to changes in velocity.
3. In the vacuum of space, where there are minimal external forces, objects tend to maintain constant velocity as per Newton’s first law.
4. The stability of planetary orbits can be attributed to the balance between gravitational pull and inertial motion, a direct application of Newton's first law.
5. Understanding how spacecrafts travel through space relies on principles derived from Newton's first law.

Review Questions

Related terms

Gravitational Force:

The attractive force between two masses which is crucial for maintaining orbital paths.

Inertia:

The tendency of an object to resist changes in its state of motion.

Orbital Mechanics:

The study of the motions of artificial satellites and natural celestial bodies influenced primarily by gravitational forces.