Question 1

What is the value of the universal gravitational constant ($G$)?

Accepted Answer

The universal gravitational constant $G$ has a value of $6.673 	imes 10^{-11} 	ext{ N m}^2/	ext{kg}^2$. This value was first accurately calculated by Henry Cavendish using a torsion balance.

Question 2

The SI unit of the universal gravitational constant ($G$) is:

Accepted Answer

According to the universal law of gravitation, $F = G \frac{m1 m2}{d^2}$, rearranging for $G$ gives $G = \frac{F \cdot d^2}{m1 m2}$. Substituting the units gives $	ext{N} \cdot 	ext{m}^2/	ext{kg}^2$ or $	ext{N m}^2 	ext{kg}^{-2}$.

Question 3

The force of gravitation between two objects is proportional to:

Accepted Answer

According to the universal law of gravitation, 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 them.

Question 4

What happens to the gravitational force between two objects if the distance between them is halved?

Accepted Answer

Since $F \propto \frac{1}{d^2}$, if the distance $d$ is halved ($d/2$), the force becomes inversely proportional to $(d/2)^2 = d^2/4$, which means the force increases by a factor of 4.

Question 5

The value of acceleration due to gravity ($g$) on the surface of the earth is:

Accepted Answer

The standard average value of acceleration due to gravity on the surface of the earth is approximately $9.8 	ext{ m/s}^2$. It varies slightly depending on latitude and altitude.

Gravitation — CBSE Class 9 Science Important Questions & Revision Notes