The force P$,$ which is applied to the $18\mathrm{.}0-$kg block initially at rest, varies linearly with the time as indicated. If the coefficients of static

and kinetic friction between the block and the horizontal surface are $0\mathrm{.}37$ and $0\mathrm{.}31,$ respectively, determine the velocity of the block

when t $=4\mathrm{.}0$ s$.$ The force $\backslash ($ P $\backslash ),$ which is applied to the $18\mathrm{.}0-$kg block initially at rest, varies linearly with the time as indicated. If the coefficients of static and kinetic friction between the block and the horizontal surface are $0\mathrm{.}37$ and $0\mathrm{.}31,$ respectively, determine the velocity of the block when $\backslash ($ t$=4\mathrm{.}0\backslash$mathrm$\{$~s$\}\backslash ).$