Question

The driver is looking at her phone and has a total reaction time of 4.6 seconds as the car is moving at a constant speed of 11m/s. If the driver slams in her brake and slow down at a rate of -8.2m/s, what is the stopping distance for a car in this situation?

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Answer 1

The stopping distance is 36.15m

Step-by-step explanation:

In this exercise we are going to apply the second equation of motion to model the situation

`s=ut-(1)/(2)at^2`

Given data

time in seconds= 4.6 seconds

speed v= 11 m/s

deacceleration a= 8.2m/s

Substituting this values into the expression for distance we have

`s=11*4.6-(1)/(2)*8.2*4.6^2 \\\\s=50.6-(1)/(2)*8.2*21.16 \\\\s=50.6-(1)/(2)*173.512 \\\\\s=50.6-86.756 \\\\s=36.15m`

The stopping distance is 36.15m