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1 vote
The driver of a car traveling at 50 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 Pitarou
by
7.8k points

2 Answers

5 votes
s(t) = 50t - 2t^2
v(t) = 50 - 4t
a(t) = -4

When v(t) = 0, the car stops.
v = u +at
0 = 50 + (-4)t
t=12.5s



User Mlclm
by
8.7k points
5 votes

Answer:

The car come to a stop in 12.5 seconds after the driver applies the brakes

Explanation:

Given :The position of the car is
s(t) = 50t - 2t^ 2, t seconds after the driver applies the brakes.

To Find : How many seconds after the driver applies the brakes does the car come to a stop?

Solution:


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


V =(ds)/(dt)

Where V is Speed of car

So,
V =(d(50t - 2t^ 2))/(dt)


V =50-4t

So,Speed of the car is
V =50-4t

Now we are supposed to find How many seconds after the driver applies the brakes does the car come to a stop.

So, Substitute V = 0


0 =50-4t


4t=50


t=(50)/(4)


t=12.5

Hence the car come to a stop in 12.5 seconds after the driver applies the brakes

User QuasarDJ
by
8.7k points
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