Gravitation

Which of the following statements is true of the value of acceleration due to gravity?

• 1. The value is the same on the equator and poles.

• 1. The value is least on poles.

• 1. The value is almost negligible on the equator.

• 1. The value increases from pole to equator.

Answer explanation

Answer: (c) The value is almost negligible on the equator

Explanation: The acceleration value due to gravity is least on the equator.

Which of the following factors does the acceleration due to gravity on the Earth depend upon?

• 1. Mass of the Body

• 1. Mass of the Earth

• 1. The volume of the Body

• 1. Shape and Size of the Body

Answer explanation

Answer: (b) Mass of the Earth

Explanation: The acceleration due to gravity on the Earth depends upon the mass of the Earth.

The weight of an object on the Moon’s surface is

• 1. 1/3 ^rd of the weight on Earth

• 1. 1/5 ^rd of the weight on Earth

• 1. 1/6^th of the weight on Earth

• 1. 1/2 ^nd of the weight on Earth

Answer explanation

Answer: (c) 1/6^th of the weight on Earth

Explanation: The weight of an object on the Moon’s surface is 1/6^th of the weight on Earth.

Which law states that the gravitational force between two objects is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centers?

• Kepler’s First Law

• Kepler’s Second Law

• Newton’s First Law

• Newton’s Law of Universal Gravitation

Answer explanation

Answer: d) Newton’s Law of Universal Gravitation

The gravitational force between two objects is F. If masses of both objects are halved without changing distance between them, then the gravitational force would become

• F/4

• F/2

• F

• 2 F

Answer explanation

Answer is (a) F/4

The value of quantity G in the law of gravitation

• depends on mass of earth only

• depends on radius of earth only

• depends on both mass and radius of earth

• is independent of mass and radius of the earth

Answer explanation

Answer is (d) is independent of mass and radius of the earth

Explanation:

G is an universal constant hence it is independent of mass and radius of the earth.

The weight of an object at the centre of the earth of radius R is

• zero

• infinite

• R times the weight at the surface of the earth

• 1/R² times the weight at surface of the earth

Answer explanation

Answer is (a) zero

Explanation:

At the centre of the earth acceleration due to gravity is zero. Since weight is the product of mass and gravity. Weight of the object at the centre of the earth will be zero.

The value of G Universal law of gravitation is –

• 6.673×10¹¹NM²Kg⁻² 

• 6.673×10¹°NM²Kg² 

• 6.673×10⁻¹°NM²Kg⁻² 

• 6.673×10⁻¹¹NM²Kg⁻² 

Answer explanation

Ans (d)6.673×10⁻¹¹NM²Kg⁻² 

Which of the following is correct

• thrust

  pressure = ————

                      area

•     area

  pressure = ————

                        thurst

• pressure = thrust × area

• pressure = thrust + area

Answer explanation

Ans:  

                          thrust

pressure = ————

                           area

Which of the following has no unit? 

• density 

• relative density 

• pressure 

• thrust 

Answer explanation

Ans: (b) relative density.