Answer:
Explanation:
The given equation is :
In very early human history, complex sanitation systems were not needed because settlements were usually very small, like the vi
llage shown below.
However, as cities became larger and population densities increased, one major advancement was the development of _______, which helped to channel wastewaters away from human populations more effectively than in the past.
A.
fountains
B.
water towers
C.
sewer systems
D.
dams
However, as cities became larger and population densities increased, one major advancement was the development of _______, which helped to channel wastewaters away from human populations more effectively than in the past.
A.
fountains
B.
water towers
C.
sewer systems
D.
dams
2 answers:
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Answer:
maximum speed for safe vehicle operation = 55mph
Explanation:
Given data :
radius ( R ) = 678 ft
old building located ( m )= 30 ft
super elevation = 0.06
<u>Determine the maximum speed for safe vehicle operation </u>
firstly calculate the stopping sight distance
m = R ( 1 - cos ) ---- ( 1 )
R = 678
m ( horizontal sightline ) = 30 ft
back to equation 1
30 = 678 ( 1 - cos (28.655 *s / 678 ) )
( 1 - cos (28.655 *s / 678 ) ) = 30 / 678 = 0.044
cos = 1.044
hence ; 28.65 * s = 678 * 0.2956
s = 6.99 ≈ 7 ft
next we will calculate the design speed ( u ) using the formula below
S = 1.47 ut + ---- ( 2 )
t = reaction time, a = vehicle acceleration, G1 = grade percentage
assuming ; t = 2.5 sec , a = 11.2 ft/sec^2, G1 = 0
back to equation 2
6.99 = 1.47 * u * 2.5 +
3.675 u + 0.0958 u^2 - 6.99 = 0
u ( 3.675 + 0.0958 u ) = 6.99