Force and Gravitation Lecture Flashcards

Vocabulary-style flashcards covering the fundamental concepts of force, gravitation, planetary hypotheses, and the properties of mass and weight based on the lecture transcript.

Gravitation

The force of attraction between any two objects in the universe.

Geocentric Hypothesis

The hypothesis which assumed that Earth is in the center of solar system.

Heliocentric Hypothesis

The hypothesis which assumed that Sun is in the center of solar system; it was propounded by Nicholas Copernicus in 1542 AD.

Newton’s Universal Law of Gravitation

States that the force of attraction between any two objects in the universe is directly proportional to the product of their masses and inversely proportional to the square of distance between their centers.

Universal Gravitational Constant ($G$)

The gravitational force of attraction between two objects of unit masses kept at unit distance; its value is $6.67 \times 10^{-11}\,Nm^2kg^{-2}$ and was calculated by Henry Cavendish.

Gravity

The force by which Earth pulls any objects towards its center.

Acceleration

The rate of change of velocity per unit time.

Newton’s Second Law of Motion

States that the acceleration produced on a body is directly proportional to force applied and inversely proportional to the mass of body.

Acceleration due to gravity ($g$)

The acceleration produced on a body falling freely towards the surface of Earth under the action of its gravity, with an average value of $9.8\,m/s^2$.

Coin and Feather Experiment

An experiment performed by Robert Boyle demonstrating that in the absence of air resistance, both objects fall together regardless of mass.

Mass

The amount of matter contained by the object; it is constant, measured in $kg$ using a beam balance.

Weight

The force of attraction by which Earth pulls any objects towards its center; it is variable, measured in Newton ($N$) using a spring balance.

Variation of $g$ at Equator and Poles

Due to Earth's shape, the radius is more at the equator ($R_{equator} > R_{poles}$), making acceleration due to gravity maximum at poles ($g_{poles} > g_{equator}$).

Freefall

The condition when an object falls freely under the action of gravity in the absence of air resistance.

Weightlessness

The condition at which the weight of a body is considered to be zero, such as during freefall or in space where $g = 0\,m/s^2$.