A 1200-ft equal-tangent crest vertical curve is currently designed for 50 mi/h. A civil engineering student contends that 60 mi/
h is safe in a van because of the higher driver’s-eye height. If all other design inputs are standard, what must the driver’s-eye height (in the van) be for the student’s claim to be valid?
1 answer:
Response:
8.95ft
Explanation:
For tackling this issue, two key concepts should be evaluated:
First, the design of vertical curves should be considered using the general equation defining the length of a vertical crest curve, based on the differences in gradients. Also, the Design Controls for Crest vertical curves table is useful (a table is attached at the bottom).
The equation for this is written as:
Where,
L = length of vertical curve
S = Sight distance
A = Algebraic difference in gradients
Height of eye above road level
height of object above road surface
From the provided table, it's determined that at a design speed of 60 mi/h, S measures 570 ft. The vertical curve rate K at a design speed of 50 mi/h is 84.
Next, we can calculate the algebraic difference in gradients as follows:
Using the equation to calculate , we find:
Solving for
Thus, the height of the driver's eye is 8.95ft
You might be interested in
Answer:
Explanation:
Given,
Voltage of the primary coil (V_p) = 30 kV-rms
Voltage of the secondary coils (V_s) = 345 kV-rms
number of turns in the primary coil (n_p) = 80 turns
number of turns in the secondary coil (n_s) =?
the ratio of turns between primary and secondary coils
The number of turns in the secondary coil is equal to
Complete Question:
Picture yourself on an aluminum ladder on the ground, attempting to fix an electrical connection with a metal screwdriver featuring a metallic handle. Since you are sweating profusely, your body has a resistance of 1.60 kΩ.
(a) If you accidentally contact the "hot" wire from the 120 V power line, what current will flow through your body?
(b) What is the amount of electrical power transferred to your body?
Answer:
(a) 0.075A
(b) 9W
Explanation:
According to Ohm's law, the voltage (V) applied to or passing through a body corresponds to the current (I) via the relationship:
V ∝ I
=> V = I x R ----------------------(i)
Where;
R denotes the resistance of the body
(a) As mentioned;
Due to wet conditions, the body will conduct electricity, and possesses the following values;
V = supplied voltage = 120V
R = resistance of the wet body = 1.60kΩ = 1.6 x 1000Ω = 1600Ω
Substituting these values into equation(i):
120 = I x 1600
To find I;
I =
I = 0.075A
Thus the current passing through your body is 0.075A
(b) Electrical power (P), which is expressed in Watts (W), delivered to the body is the product of current (I) and voltage (V) received. Thus:
P = I x V ---------------------(ii)
Where;
I equates to 0.075A [as derived above]
V is 120V [as outlined in the question]
Plugging these values into equation (ii):
P = 0.075 x 120
P = 9W
Hence, the electrical power received by your body is 9W
Using momentum conservation, we can express it as
This implies that the speed following the collision is influenced by the mass of both objects involved.
If the masses of the two colliding objects are modified, the resulting speed shifts as well.
For instance,
When two objects share identical mass, their speeds will be exchanged post-collision.
In contrast, if one object is significantly heavier than the other, its velocity remains unchanged after the collision.
Thus, altering the mass will alter the speed of the object subsequent to the collision.
The resulting speed after the collision can be represented as
Through these formulas, we can demonstrate how the speeds are linked to the mass.