Physics: Gravitation and Centripetal Force

Gravitation

• Gravitation is an unseen force of attraction that attracts everything towards the Earth.
• The force that causes acceleration and keeps the body moving along the circular path is called the centripetal force, also known as the centre-seeking force.

Law of Gravitation

• Every object in the universe attracts every other object with a force proportional to the product of their masses and inversely proportional to the square of the distance between them.
• This is known as the law of gravitation or universal law of gravitation.

Gravitational Force

• The gravitational force between two uniform objects is directed along the line joining their centres.
• The force of attraction (F) between two masses (M) and (m) separated by a distance (d) is given by the equation: F = GMm / d^2, where G is the universal gravitational constant.
• The value of G is 6.67 × 10^-11 Nm^2/kg^2.

Importance of Universal Law of Gravitation

• The force that binds us to the Earth
• The motion of the moon around the Earth
• The motion of planets around the Sun
• The tides due to the moon and the Sun

Free Fall and Acceleration Due to Gravity

• When an object falls from a height under the influence of gravitational force, it is known as free fall.
• The acceleration involved when an object falls towards the Earth is called the acceleration due to gravity (g).
• The unit of g is m/s^2, and its mathematical expression is: g = GM / R^2.
• The value of acceleration due to gravity on Earth is 9.8 m/s^2.

Mass

• The mass of a body is the quantity of matter contained in it.
• Mass is a scalar quantity with only magnitude but no direction.