You may have noticed runaway truck lanes while driving in the mountains. these gravel-filled lanes are designed to stop trucks that have lost their brakes on mountain grades. typically, such a lane is horizontal (if possible) and about 34.5 m34.5 m long. think of the ground as exerting a frictional drag force on the truck. a truck enters a typical runaway lane with a speed of 54.0 mph54.0 mph ( 24.1 m/s24.1 m/s ). use the work-energy theorem to find the minimum coefficient of kinetic friction between the truck and the lane to be able to stop the truck.