You testify as an expert witness in a case involving an accident in which car A slid into the rear of car B, which was stopped at a red light along a road headed down a hill (Fig. 6-25). You find that the slope of the hill is θ = 12.0^o, that the cars were separated by distance d = 24.0 m when the driver of car A put the car into a slide (it lacked any automatic anti-brake-lock system), and that the speed of car A at the onset of braking was v₀= 18.0 m/s. With what speed did car A hit car B if the coefficient of kinetic friction was?

(a) 0.60 (dry road surface) and?

(b) 0.10 (road surface covered with wet leaves)?