At a given instant the $\backslash (10-\backslash$mathrm$\{$lb$\}\backslash )$ block $\backslash ($ A $\backslash )$ in $($Figure $1).$ is moving downward with a speed of $\backslash (6\backslash$mathrm$\{$ft$\}/\backslash$mathrm$\{$s$\}\backslash ).$

Figure

Part A

Determine its speed $1$ s later if block $\backslash ($ B $\backslash )$ has a weight of $4$ lb $,$ and the coefficient of kinetic friction between it and the inclined plane is $\backslash (\backslash$mu$\_\{\backslash$mathrm$\{$k$\}\}=0\mathrm{.}2\backslash ).$ Neglect the mass of the pulleys and cord.

Express your answer in feet per second to three significant figures.

$\backslash [$

$\backslash$mathrm$\{$ft$\}/\backslash$mathrm$\{$s$\}$

$\backslash ]$

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