far will it skid on wet tar?

Police use the formula s = 30fd to estimate the speed s (in mi/h) at which a car is traveling if it skids d feet after the brakes are applied suddenly. The number f is the coefficient of friction of the road, which is a measure of the "slipperiness" of the road. The table gives some typical estimates for f. Tar Concrete Gravel Dry Wet 1.0 0.5 0.8 0.4 0.2 0.1 (a) If a car skids 100 ft on wet concrete, how fast was it moving when the brakes were applied? (Round your answer to the nearest whole number.) mi/h (b) If a car is traveling at 32 mi/h, how far will it skid on wet tar? (Round your answer to the nearest foot.)