A $1993$ Ford Ranger $($Area $=33$ ft$2,$ W$=4,000$

lbs$)$ has a maximum tractive effort of $400$

lb$.$ If the car is travelling at sea level $(\backslash$rho $=0\mathrm{.}002378$ slugs$/$ft$3),$ assume $0\mathrm{.}45$ drag

coefficient:

$(1)$ what is the maximum speed it can reach

on level ground, and

$(2)$ what is the maximum grade it can

ascend and maintain $55$ mph$?35$ mph$?$