107 775
Assignments Done
100%
Successfully Done
In July 2024

# Answer to Question #155243 in Civil and Environmental Engineering for lameck omenyi

Question #155243

a test of a driver's perception reaction time is being conducted on a special testing track with wet pavement and a driving speed of 50 kph. when the driver is sober, a stop can be made just in time to avoid hitting an object that is visible 40 m. ahead. after a few drinks of san miguel beer, under exactly the same condition, the driver fails to stop in time and strikes the object at a speed of 30 kph. determine the driver's perception-reaction time after he was drinking. assume coefficient of friction is 0.60.

1
2021-01-19T05:19:41-0500

"d= v"1 "\\times tr"

"d=" distance travelled for perception

"v"1 = initial velocity

"tr"= perception time

"tr" ="\\frac{d}{v1}" = "\\frac{40}{50}= 0.8 seconds"

coefficient of friction "\\mu" = "\\frac{force applied }{normal weight }"= "\\frac{ma}{mg}"

0.6="\\frac{mg}{ma}= \\frac{ma}{m\\times 9.81}"

"a=9.81\\times0.6=5.886 m\/s"

"a" (acceleration/deceleration) = "\\frac{final velocity- initial velocity}{time^2}"

= "\\frac{mg}{t}" ="v"v- "v"u/t"2"

5.886= "\\frac{0-30}{t^2}=equivalent = \\frac{30}{t^2}"

t= "\\sqrt[]{\\frac{30}{5.886}} = 2.258 seconds"

total perception time for the unconscious driver is therefore prolonged as below;

t= 0.8 + 2.258

= 3.058 seconds

Need a fast expert's response?

Submit order

and get a quick answer at the best price

for any assignment or question with DETAILED EXPLANATIONS!