178k views
3 votes
The driver of a car traveling at 60 ft/sec suddenly applies the brakes. The position of the car is s(t) = 50t − 2t2, 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 Adam Reed
by
7.9k points

1 Answer

4 votes

Answer: 12.5 seconds

Explanation:

To find out how many seconds after the driver applies the brakes the car comes to a stop, we need to find the value of t when the car's velocity, s'(t), is equal to 0. The velocity of the car is the derivative of the position function, so we can find it by differentiating s(t).

s(t) = 50t - 2t^2

s'(t) = 50 - 4t

To find when the velocity is 0, we set s'(t) = 0 and solve for t:

0 = 50 - 4t

4t = 50

t = 50/4

t = 12.5 seconds

Therefore, it takes the car 12.5 seconds to come to a stop after the driver applies the brakes.

User Abhinav Gupta
by
7.7k points