- #1
jrjack
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Homework Statement
The driver of a car traveling at 71 ft/sec suddenly applies the brakes. The position of the car is s = 71t - 20t2, t seconds after the driver applies the brakes. After how many seconds does the car come to a stop? Round your answer to the nearest tenth.
Homework Equations
The Attempt at a Solution
s=71t-20t2
0=71t-20t2
0=71-20t
t=71/20
t=3.55 = 3.6
However the correct answer is 1.8, which is half my answer, but I do not understand why you would divide by 2? Or where I went wrong?