Question
State Newton's law of gravitation.
✓
Answer
This law states that the force of attraction acting between two particles is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.
i.e. $F \propto m_1 m_2$
And $F \propto \frac{1}{r^2}$
Combining (i) and (ii), we have
$
\begin{array}{l}
F \propto \frac{m_1 m_2}{r^2} \\
\text { or } F=\frac{G m_1 m_2}{r^2}
\end{array}
$
Where G is the constant of proportionality and is known as the universal gravitational constant. Its value at all places in this universe is $6.67 \times 10^{-11} Nm ^2 kg^{-2}$.
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