185- In the figure below, an object is released from the top of an inclined surface and reaches the bottom surface with a speed of $15\,\dfrac{\text{m}}{\text{s}}$. The coefficient of kinetic friction of the object with the surface is how much? $\left(g = 10\,\dfrac{\text{m}}{\text{s}^2},\ \sin 53^\circ = 0.8\right)$ [Figure: inclined plane with $h = 20\,\text{m}$ and angle $53^\circ$] (1) $\dfrac{3}{4}$ (2) $\dfrac{7}{12}$ [10pt] (3) $\dfrac{1}{3}$ (4) $\dfrac{1}{6}$
\textbf{185-} In the figure below, an object is released from the top of an inclined surface and reaches the bottom surface with a speed of $15\,\dfrac{\text{m}}{\text{s}}$. The coefficient of kinetic friction of the object with the surface is how much? $\left(g = 10\,\dfrac{\text{m}}{\text{s}^2},\ \sin 53^\circ = 0.8\right)$
\textit{[Figure: inclined plane with $h = 20\,\text{m}$ and angle $53^\circ$]}
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(1) $\dfrac{3}{4}$ \hspace{2cm} (2) $\dfrac{7}{12}$ \\[10pt]
(3) $\dfrac{1}{3}$ \hspace{2cm} (4) $\dfrac{1}{6}$
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