Question

A suitable unit for gravitational constant is

• A. $kg-m{s}^{-1}$
• B. $N{m}^{-1}s$
• C. $N{m}^{2}k{g}^{-2}$
• D. $kgm{s}^{-1}$

Answer 1

The correct option is C

$N{m}^{2}k{g}^{-2}$

Explanation for correct option:

1. Gravitation force between two masses is given by $F=\frac{GMm}{r^2}$, where, $G$ is universal gravitational constant, $M$and $m$are two masses and $r$is the distance between them.
2. Now we rewrite the formula as, $G=\frac{F{r}^2}{Mm}$
3. Unit of force is Newton (N), unit of distance is meter (m), unit of mass is kilogram (kg).
4. Therefore unit of gravitational constant is $N{m}^{2}k{g}^{-2}$.

Hence, option (C) is correct.