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. you find that the slope of the hill is θ = 12.0°, that the cars were separated by distance d = 25.0 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.

(a) with what speed did car a hit car b if the coefficient of kinetic friction was 0.60 (dry road surface)?
m/s

(b) what was the speed if the coefficient of kinetic friction was 0.10 (road surface covered with wet leaves)?
m/s