The brakes are applied to a car traveling on a dry, levelhighway. A typical value for the magnitude of the car'sacceleration is 5.35 m/s2. Ifthe car's initial speed is 29.7 m/s, howlong does it take to stop and how far does it travel, starting fromthe moment the brakes are applied? a)time to stop_____s b)stopping distance____m The brakes are applied to a car traveling on a dry, levelhighway. A typical value for the magnitude of the car'sacceleration is 5.35 m/s2. Ifthe car's initial speed is 29.7 m/s, howlong does it take to stop and how far does it travel, starting fromthe moment the brakes are applied? a)time to stop_____s b)stopping distance____m
Explanation / Answer
a) To find the time it takes to stop, use the equation t =(vf - vo) / a = (0 m/s - 29.7 m/s)/(5.35m/s2) = 5.55s. b) To find the stopping distance, use the equation x =vot + at2/2 = (29.7 m/s)(5.55s) + (-5.35m/s2)(5.55s)2/2 = 82.4m.