Question

As a city planner, you receive complaints from local residents about the safety of nearby roads and streets. One complaint concerns a stop sign at the corner of Pine Street and 1st Street. Residents complain that the speed limit in the area (55 mph) is too high to allow vehicles to stop in time. Under normal conditions this is not a problem, but when fog rolls in visibility can reduce to only 155 ft.155 ft. Since fog is a common occurrence in this region, you decide to investigate.

The state highway department states that the effective coefficient of friction between a rolling wheel and asphalt ranges between 0.689 and 0.770, whereas the effective coefficient of friction between a skidding (locked) wheel and asphalt ranges between 0.450 and 0.617. Vehicles of all types travel on the road, from small VW bugs weighing 1090 lb to large trucks weighing 8820 lb.

Considering that some drivers will brake properly when slowing down and others will skid to stop, calculate the minimum and maximum braking distance needed to ensure that all vehicles traveling at the posted speed limit can stop before reaching the intersection.

minimum braking distance: ft

maximum braking distance: ft

Given that the goal is to allow all vehicles to come safely to a stop before reaching the intersection, calculate the maximum desired speed limit.

maximum speed limit: mph

Which factors affect the soundness of your decision?

Reaction time of the drivers is not taken into account.

Drivers cannot be expected to obey the posted speed limit.

Precipitation from the fog can lower the coefficients of friction.

Newton's second law does not apply to this situation.

Answer 1

2 Morin = 0.689 Mmax = 0.770 Speed = u = 55 mph 55+ 55 X 1.609 kmph. : 55X 1060g x Smols u² 604.270 i minimum distance = Smi = ... 40.03 m zug 2X0.770X9.8 maximum distance : 42 604-270 2 perang 2X0.689x98) smax 44.74 m for speed, distance = $ - 155 ft : 4.724 m. fined velocity initial velocity u = √ augs. VO. U. v² u't zugs - u= va 2X0.45049.884.72 U-6.5 m/s = 23.4 kmph CS Scanned with CamScanner