Unit 2 · 2.6 — Gravitational Force

Everything to learn here

• Concept: Gravitational force is an attractive, fundamental force acting between any two masses, decreasing with the square of the distance between their centers.
• Concept: Inertial mass (resistance to acceleration) is experimentally equivalent to gravitational mass (response to a gravitational field).
• Concept: The acceleration due to gravity (g) on a planet's surface depends on the planet's mass and radius, not the falling object's mass.
• Concept: The force of gravity on an object near a planet's surface (weight) is proportional to its mass and the local gravitational field strength.
• Equation: $$F_g=m\cdot g\text{(Local force of gravity or weight)}$$
• Equation: $$F_G=G\cdot \frac{m_1\cdot m_2}{r^2}\text{(Newton’s Law of Universal Gravitation)}$$
• Equation: $$g=G\cdot \frac{M}{r^2}\text{(Gravitational Field Strength / Free-fall acceleration on a planet)}$$
• Vocabulary: Gravitational Field (g) — A model describing the gravitational force per unit mass exerted at any point in space by a massive object.
• Vocabulary: Weight — The magnitude of the gravitational force exerted on an object.
• Skill: Mathematical Routines — Deriving the symbolic expression for the gravitational field strength on a planet given its mass and radius as ratios of Earth's.

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