Question 15: Gravitation

Question

The unit of universal gravitational constant is :

Accepted Answer

Starting from NewtonÃ¢ÂÂs law of gravitation:
$$F \;=\; G\,\frac{m_1\,m_2}{r^2}$$
Solving for $G$:
$$G \;=\; F\,\frac{r^2}{m_1\,m_2}$$
Now, in terms of units:
$[F]=	ext{N}= 	frac{	ext{kg}\,	ext{m}}{	ext{s}^2}$
$[r]=	ext{m}$
$[m_1]=[m_2]=	ext{kg}$
So
$$[G] \;=\; \frac{\bigl(	frac{	ext{kg}\,	ext{m}}{	ext{s}^2}\bigr)\,	ext{m}^2}{	ext{kg}^2}        \;=\; 	ext{N}\,	ext{m}^2\,	ext{kg}^{-2}$$
That matches Option D.

Answer

$\mathrm{N} \mathrm{m}^2 \mathrm{~kg}^2$

Answer

$\mathrm{N} \mathrm{m}^{-2} \mathrm{~kg}^{-2}$

Answer

$\mathrm{N} \mathrm{m}^{-2} \mathrm{~kg}^2$

Answer

$\mathrm{N} \mathrm{m}^2 \mathrm{~kg}^{-2}$

Gravitation

The unit of universal gravitational constant is :

Choose the correct answer: