Traffic Court. You are called as an expert witness in a trial for a traffic violation. The facts are these: A driver slammed on his brakes and came to a stop with constant acceleration. Measurements of his tires and the skid marks on the pavement indicate that he locked his car's wheels, the car traveled $192 \mathrm{ft}$ before stopping, and the coefficient of kinetic friction between the road and his tires was $0.750 .$ He was charged with speeding in a $45 \mathrm{mi} / \mathrm{h}$ zone but pleads innocent. What is your conclusion: guilty or innocent? How fast was he going when he hit his brakes?