\textbf{164.} A body of mass $2\,\text{kg}$ slides on an inclined surface that makes an angle of $30°$ with the horizontal, moving downward at constant speed. If in this motion the body is displaced $2\,\text{m}$, how much work (in Joules) does the friction force do? $\left(g = 10\,\dfrac{\text{m}}{\text{s}^2}\right)$
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$-25\sqrt{3}\ (1$ \hspace{1cm} $-10\sqrt{3}\ (2$ \hspace{1cm} $-10\ (3$ \hspace{1cm} $-20\ (4$
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