NCERT Solutions for Chapter: Gravitation, Exercise 2: MCQ-II

Which of the following options is correct?

If the law of gravitation, instead of being inverse-square law, becomes an inverse-cube law:

If the mass of the sun were ten times smaller and the gravitational constant $G$ were ten times larger in magnitudes.

If the sun and the planets carried huge amounts of opposite charges,

There have been suggestions that the value of the gravitational constant $G$ becomes smaller when considered over a very large time period (in billions of years) in the future. If that happens, for our earth

Supposing Newton's law of gravitation for gravitation forces ${\overrightarrow{F}}_1\text{ and }{\overrightarrow{F}}_2$  between two masses is $m_1\text{ and }{m}_2$ at positions ${\overline{r}}_1\text{ and }{\overline{r}}_2\text{ read }\overline{F}$$=-{\overrightarrow{F}}_2=-\frac{{\overrightarrow{r}}_{12}}{r_{12}^3}G{M}_0^2\left[\frac{m_1{m}_2}{M_0^2}\right]$ where $M_0$ is a constant of the dimension of mass, ${\overrightarrow{r}}_{12}={\overrightarrow{r}}_1-{\overrightarrow{r}}_2$ and $n$ is number. In such a case

Which of the following are true?

The centre of mass of an extended body on the surface of the earth and its centre of gravity