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Doc Al
#5
Jan7-13, 01:36 PM
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Quote Quote by shounakbhatta View Post
Sorry,

F=G.m1.m2/r^2

Can it be written:
F=-G.m.m/r^2.
Sometimes when writing the force as a vector expression a minus sign is used to indicate that it's an attractive force:

[tex]\vec{F} = - \frac{G m_1 m_2}{r^2} \hat{r}[/tex]
Where [itex]\vec{r}[/itex] is the position vector of m_2 with respect to m_1 and [itex]\vec{F}[/itex] is the gravitational force on m_2 due to m_1.

See: Vector form