The reaction time for an automobile driver is 0.7 sec.If the automobile can be decelarated at 5 m/s^2 calculate the total distance travelled in coming to stop from an initial velocity of 8.33 m/s after a signal is observed?

1 Answer
Roy Ø.
Jun 20, 2018

The car will move 13.60 m

Explanation:

We have distance #s=vt#
#v_1= v_0+at#
Before the driver reacts, the car will have moved
#s_1=8.33*0.7 m=5.831 m#
The time for the car to stop can be found from
#v_1= v_0+at#
#0=9.33-5t# or t=1.866 s
The average speed during this time is #v_a=1/2*8.33 m/s=4.165 m/s#
Therefore, the car moves #4.165*1.866# m =7.772m

Total distance moved before the car stops, therefore, is
(5.831+7.772) m = 13.603 m
Rounded to 2 decimals: 13.60 m

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