College Physics with MasteringPhysics 7th Edition by Jerry Wilson,Anthony Buffa,Bo Lou

Exercise 40

A car is traveling on a straight, level road under wintry conditions. Seeing a patch of ice ahead of her, the driver of the car slams on her brakes mid skids on dry pavement for 50 m, decelerating at 7.5 m/s 2. Then she hits the icy patch and skids another 80 m before coming to rest. If her initial speed was 70 mi/h, what was the deceleration on the ice