#3: Newton's Law of Gravitation

These flashcards cover the key concepts of Newton's law of gravitation, including its historical context, fundamental equations, and key experiments related to gravitational measurements.

What can be predicted using Newton's law of gravitation?

The return of a comet and its exact path.

What is the concept that gravity is universal?

Any two masses exert a force of attraction on each other.

What did Johannes Kepler demonstrate about planetary motion?

The motion of the planets is governed by a set of laws.

What is Kepler's third law?

The square of the orbital period of a planet is proportional to the cube of the semi-major axis of its orbit.

How does Newton's law of gravitation relate the force of gravity to distance?

Gravity varies inversely with the square of the distance between two masses.

What is the universal constant of gravitation denoted as?

G.

What is the value of G?

6.67 x 10^-11 Nm² kg^-2.

What constitutes the gravitational force equation according to Newton's law of gravitation?

F = G(m₁m₂)/r².

What apparatus did Henry Cavendish use to measure G?

A torsion balance.

How did Cavendish determine the force of attraction in his experiment?

By measuring the angle the torsion wire twisted when lead balls were brought near.

Why can the Sun and the Earth be considered point masses for gravitational calculations?

Their sizes are negligible compared to the distance between them on a distance scale.

What is the force of gravitational attraction between the Sun and the Earth?

Approximately 3.6 x 10^22 N.