Part 2: Which of the following affect the soundness of your decision? 1. Drivers

Question

Part 2: Which of the following affect the soundness of your decision?

1. Drivers cannot be expected to obey the posted speed limit.

2. Precipitation from the fog can lower the coefficients of friction.

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

4.Reaction time of the drivers is not taken into account.

Map Sapling Learning 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 (89 km/h) 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 47 meters. Since fog is a common occurrence in this region, yo u decide to investigate The state highway department states that the effective coefficient of friction between a rolling wheel and asphalt ranges between 0.842 and 0.941, whereas the effective coefficient of friction between a skidding (locked) wheel and asphalt ra small VW bugs with a mass of 571 kg to large trucks with mass 4063 kg s between 0.550 and 0.754. Vehicles of all types travel on the road, from Considering that some drivers will brake properly when slowing down and others will skid to stop, calculate the miminim and maximum braking distance needed to ensure that all vehicles traveling at the posted speed limit can stop before reaching the intersection Minimum Maximum Number Number ITm IIn 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. Number (Scroll down for more questions.) km/ h Previous O Check Answer Next Exit Hint

Explanation / Answer

Part 2: Which of the following affect the soundness of your decision?

Answer :

1. Drivers cannot be expected to obey the posted speed limit.

2. Precipitation from the fog can lower the coefficients of friction..

4.Reaction time of the drivers is not taken into account.

form the given data
coefficient of friction for rolling tyre, kr = 0.842 to 0.941
coefficient for skidding friction, ks = 0.550 to 0.754

hence minimum stopping distance = dmin
2*0.941*9.81*dmin = v^2
v = speed limit = 89 km/h = 24.7222m/s
hence
dmin = 33.10439 m

similiarly
dmax = 56.638 m

hence dmax should be 47 m
so, new speed limit = u
2*0.550*9.81*47 = u^2
u = 22.52059 m/s = 81.074 km/hr

part 2:

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