Gravitation

Gravitation is the natural force of attraction between any two objects in the universe. Every object, whether big or small, attracts every other object with this force. This is called the gravitational force.

Newton’s Universal Law of Gravitation:
Every object in the universe attracts every other object with a force which is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centers.
Formula: F = G × (m₁ × m₂) / r²
Here,
F = gravitational force between two objects
m₁ and m₂ = masses of the two objects
r = distance between their centers
G = universal gravitational constant (6.67 × 10⁻¹¹ N·m²/kg²)

Gravity:
The Earth attracts all objects towards its center. This force of attraction is called gravity. Due to gravity, objects fall towards the Earth when dropped.

Acceleration due to Gravity (g):
When an object falls freely under the influence of gravity, it has an acceleration called acceleration due to gravity.
Its value on Earth is about 9.8 m/s².

Mass and Weight:

Mass is the amount of matter in a body. It remains constant everywhere.

Weight is the force with which the Earth attracts a body.
Formula: Weight = Mass × Gravity (W = m × g)
Weight changes from place to place because the value of g changes.

Free Fall:
When an object falls only under the influence of gravity and no other force acts on it, the motion is called free fall.

Thrust and Pressure:
Thrust is the total force acting perpendicularly on a surface.
Pressure is the force acting per unit area.
Formula: Pressure = Force / Area
Pressure decreases if the area increases.

Archimedes’ Principle:
When a body is immersed in a fluid, it experiences an upward force equal to the weight of the fluid displaced by it. This explains why some objects float and others sink.

Relative Density:
Relative density is the ratio of the density of a substance to the density of water.
Formula: Relative Density = Density of substance / Density of water.

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Questions on Gravitation

Showing 61–90 of 153

61.Which of the following is NOT true about the acceleration due to gravity (g)? 62.The concept of gravitation explains why: 63.If the gravitational force between two objects is F, and the masses of both objects are doubled, the new force will be: 64.What is the acceleration of a body projected upwards when it reaches half of its maximum height? 65.Which of the following is an example of free fall? 66.The constant 'G' is called universal because: 67.The atmosphere of Earth is held by: 68.If two planets have the same mass but different radii, the planet with the larger radius will have: 69.When a body is projected vertically upwards, its speed at the highest point is: 70.The formula for gravitational potential energy (PE) for an object of mass m at height h near Earth's surface is: 71.The gravitational potential energy of an object at a certain height above the ground is: 72.Which of the following is true about the gravitational force between two apples kept on a table? 73.The ratio of the acceleration due to gravity on the surface of the Earth to that on the surface of the Moon is approximately: 74.The acceleration due to gravity 'g' is: 75.If the Earth stops rotating, the value of g at the equator will: 76.The force of attraction between two bodies does not depend on: 77.When you jump up, the Earth also moves towards you, but you don't observe it. This is because: 78.A stone is dropped from a height h. The time it takes to reach the ground is t. If it is dropped from a height 4h, the time taken will be: 79.The gravitational force between two masses m1 and m2 separated by a distance r is F. If the distance is increased to 2r, the new force will be: 80.A satellite orbiting the Earth continuously falls towards the Earth but does not hit it because: 81.Which statement is true about weight? 82.Which statement is true about mass? 83.What is the weight of a 10 kg object on Earth? (Assume g = 9.8 m/s²) 84.The factor 'G' in the universal law of gravitation is called: 85.If an object is thrown vertically upwards, its acceleration at the highest point of its trajectory is: 86.Who stated that all objects fall at the same rate in a vacuum, regardless of their mass? 87.What happens to the acceleration due to gravity (g) when you go deeper into the Earth? 88.The acceleration of a freely falling object near the Earth's surface is approximately: 89.The gravitational force between two objects is independent of the: 90.Why do astronauts experience weightlessness in orbit?