(a) Calculate the force (in N) needed to bring a 900 kg car to rest from a speed of 85.0 km/h in a distance of 100 m (a fairly typical distance for a non-panic stop). N (b) Suppose instead the car hits a concrete abutment at full speed and is brought to a stop in 2.00 m. Calculate the force exerted on the car and compare it with the force found in part (a). force in (b) force in (a)