Question

The stopping sight distance for a car traveling at 50 mph is 461 ft (including both perception-reaction distance and braking distance). The perception-reaction time is 2.5 sec. If a car traveling at 60 mph is to stop in the same distance with the same deceleration, what is most nearly the required perception-reaction time

Answer 1

Answer:

2.08 s

Explanation:

We are given that

Speed,v=50mph=73.3ft/s

1 mile=5280 feet

1 hour=3600 s

Distance,d=461 ft

t=2.5 s

v'=60 mph=88 ft/s

We have to find the perception reaction time.

Perception reaction distance=$d_p=vt=73.3\ti es 2.5=183.25 feet$

$d_p=d'_p$

$d'_p=v't$

$t'=\frac{183.25}{88}=2.08 s$