In coming to a stop, a car leaves skid marks 85 m long on the highway. Assuming a deceleration of 4.00 m/s^2, estimate the speed of the car just before braking.
The equation that is helpful to us in determining the speed of the car prior to braking is shown below, Vi² = Vf² + 2ad where Vi and Vf are initial and final velocities respectively, a is the deceleration, and d is distance. Substituting the known values, Vi² = 0² + 2(4 m/s²)(85 m) Vi = 26.08 m/s