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The driver of a car traveling at 60 ft/sec suddenly applies the brakes. The position of the car is s(t) = 60t − 1.5t2, t seconds after the driver applies the brakes. How many seconds after the driver applies the brakes does the car come to a stop?

User Dr Herbie
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8.7k points

1 Answer

3 votes

Answer:

20 seconds

Explanation:

Given:

Position of car = s(t) = 60t-1.5t^2

The speed is the change in position.

So,


Speed\ of\ car=(ds)/(dt) = (d)/(dt) (60t) -(d)/(dt) (1.5t^2)\\=60-2t(1.5)\\=60-3t

When the car will stop, the speed will be zero.


60-3t=0\\3t=60\\t = (60)/(3)\\ t=20

Therefore, the car will stop after 20 seconds of applying the break ..

User Chinni
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