Question
« previous 5 of 16 next Problem 2.26 driver of a car traveling on the highway suddenly slams on the brakes because of a slowdown in traffic ahead Part A I the cars gpeed decreases at a constant rate from 80 mi/h to 50 i/hin 30s, what is the magnilude of tis cceleration,assuming thatit continues to move in a straight line? Express your answer in miles per hour squared to two significant figures. mi/h2 Submit My Answers Give Up Part B What distance does the car travel during the braking period? Express your answer in feet to two significant figures. ft Submit My Answers Give Up Continue
Explanation / Answer
(A) vf = vi + a t
t = 3 sec = 3 / 3600 hr
50 = 80 - a(3/3600)
a = 36000 mi/h^2
(B) 50^2 - 80^2 = 2(-36000)(d)
d = 0.052 miles
d = 286 ft