The Book of Everything

 Force and Motion 

Very Short Questions: 

1.   What is gravity?

Ans: The force exerted by the planet or satellite on nearby objects is called gravity or force of gravity.

2.   State Newton’s Universal law of gravitation?

Ans: Newton’s universal law of gravitation states that, “The gravitational force between any two objects is directly proportional to the product of their masses and inversely proportional to the square of distance between them.  

3.   Write the nature of gravitational force.

Ans: The nature of gravitational force can be summarized by following points.

·   It always attracts two bodies towards each other.

·   It can act even when the two objects are not touching each other.

·   It acts between all objects in the universe that have mass, regardless of their size or distance.

4.   Define gravitational constant (G).

Ans: Gravitational constant can be defined as the force of gravitation between two bodies of unit masses separated by unit distance from their centres.  

5.   Under what conditions is the value of gravitational force equal to the gravitational constant (F = G)?

Ans: If the two bodies of 1 kg masses are separated by 1 m distance from their centre, the value of gravitational force will be equal to the gravitational constant.

6.   Write two effects of gravitational force.

Ans: The effects of gravitational force are listed below.

·   It has made the existence of the universe including the solar system possible.

·   The gravitational force between the sun and the planets causes the planets to revolve around the sun.

·   Tides occurs in seas and ocean because of the gravitational force of moon.

·   The gravitational force between earth and objects on the surface make the objects stick to the surface of the earth which makes possible to walk, run, jump etc.

7.   Mathematically present the difference in the gravitational force between two objects when the mass of each is made double and the distance between them is made one forth.