Calculate the maximum acceleration $($in m$/$s$2)$ of a car that is heading down a $6$ slope $($one that makes an angle of $6$ with the horizontal$)$ under the following road conditions. You may assume that the weight of the car is evenly distributed on all four tires and that the static coefficient of friction is involved$$that is$,$ the tires are not allowed to slip during the acceleration. $($The positive x$-$direction is up the slope. Indicate the direction with the sign of your answer.$)$

$($a$)$

on dry concrete

m$/$s$2$

$($b$)$

on wet concrete

m$/$s$2$

$($c$)$

on ice, assuming that $$s $=0\mathrm{.}100,$ the same as for shoes on ice

m$/$s$2$