DEFINITION OF REACTION TIME AND STOPPING DISTANCE WITH EQUATIONS?

Asked by swarajtopper | 1st Aug, 2015, 08:44: PM

Expert Answer:

The reaction time is the time it takes for the person to see the event and press the brakes of the car.
 
When a person is driving the car, he see an event in front of him. Now, the time taken by him to see the event and then move his feet off the pedal and to the brake and then push the brake all add up to reaction time.
 
Stopping distance is the distance travelled by the vehicle after the driver sees the event till the car stops after applying the brakes.
 
Suppose the reaction time for the driver is tr and he was driving the car with a speed v at that time, then the dstance travelled by the car in that time will be
 
begin mathsize 14px style straight d subscript straight r equals straight v cross times straight t subscript straight r end style
Similarly, the distance covered by the car after the brakes have been applied is given as
 
begin mathsize 14px style straight d subscript straight b equals vt subscript straight b minus 1 half at subscript straight b superscript 2 end style
here, a is the deceleration of the car.
 
Hence, the total stopping distance is 
 
begin mathsize 14px style straight d equals straight d subscript straight r plus straight d subscript straight b straight d equals vt subscript straight r plus vt subscript straight b minus 1 half at subscript straight b superscript 2 end style

Answered by Romal Bhansali | 2nd Aug, 2015, 12:52: PM

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