9702 · 13.2
Gravitational force between point masses
Ever wondered what keeps the Moon orbiting Earth or why you stay firmly on the ground? It's all thanks to **gravitation**, a fundamental **attractive, non-contact force** between any two objects with mass. In this lesson, we'll dive into Newton's Law of Gravitation, a powerful tool for calculating this invisible pull between **point masses**. This pilot aligns with **Senpai Corner** A Level notes (2025-2027) for topic **13.2**.
Need to know
What you need to know
- For a point outside a uniform sphere, the mass of the sphere may be considered to be a point mass at its centre.
- A uniform sphere is one where its mass is distributed evenly.
- The gravitational field lines around a uniform sphere are therefore identical to those around a point mass.
- An object can be regarded as point mass when a body covers a very large distance as compared to its size.
- Radial fields are considered non-uniform fields.
Explanation
Gravitational force between point masses
- For a point outside a uniform sphere, the mass of the sphere may be considered to be a point mass at its centre.
- A uniform sphere is one where its mass is distributed evenly.
- The gravitational field lines around a uniform sphere are therefore identical to those around a point mass.
- An object can be regarded as point mass when a body covers a very large distance as compared to its size.