If 3 varies inversely as x and y=2 when x=25, find x when y=40

An equal-tangent sag vertical curve (with a negative initial and a positive final grade) is designed for 55 mi/h. The PVI is at

Varvara68 [4.7K]

Answer:

The lowest point of the curve is at 239+42.5 ft where elevation is 124.16 ft.

Explanation:

Length of curve is given as

$L=2(PVT-PVI)\\L=2(242+30-240+00)\\L=2(230)\\L=460 ft$

$G_2$ is given as

$G_2=\frac{E_{PVT}-E_{PVI}}{0.5L}\\G_2=\frac{127.5-122}{0.5*460}\\G_2=0.025=2.5 \%$

The K value is given from the table 3.3 for 55 mi/hr is 115. So the value of A is given as

$A=\frac{L}{K}\\A=\frac{460}{115}\\A=4$

A is given as

$-G_1=A-G_2\\-G_1=4.0-2.5\\-G_1=1.5\\G_1=-1.5\%$

With initial grade, the elevation of PVC is

$E_{PVC}=E_{PVI}+G_1(L/2)\\E_{PVC}=122+1.5%(460/2)\\E_{PVC}=125.45 ft\\$

The station is given as

$St_{PVC}=St_{PVI}-(L/2)\\St_{PVC}=24000-(230)\\St_{PVC}=237+70\\$

Low point is given as

$x=K \times |G_1|\\x=115 \times 1.5\\x=172.5 ft$

The station of low point is given as

$St_{low}=St_{PVC}-(x)\\St_{low}=23770+(172.5)\\St_{low}=239+42.5 ft\\$

The elevation is given as

$E_{low}=\frac{G_2-G_1}{2L} x^2+G_1x+E_{PVC}\\E_{low}=\frac{2.5-(-1.5)}{2*460} (1.72)^2+(-1.5)*(1.72)+125.45\\E_{low}=124.16 ft$

So the lowest point of the curve is at 239+42.5 ft where elevation is 124.16 ft.

3 0

3 years ago

Problem definition

LekaFEV [45]

Answer:

ummm thats alot

Explanation:

8 0

2 years ago

Getting the bottom of your feet burned when walking on hot sand is due to what form of energy transmission? group of answer choi

Scilla [17]

Getting the bottom of your feet burned when walking on hot sand is due to a form of energy transmission known as conduction.

<h3>The types of energy transmission.</h3>

In Science, there are three (3) main types of energy transmission and these include the following:

Convection

Radiation

Conduction

In this scenario, we can infer and logically conclude that burning the bottom of your feet when walking on hot sand is primarily due to a form of energy transmission known as conduction because it involves the transfer of thermal energy (heat) due to the movement of particles.

Read more on heat conduction here: brainly.com/question/12072129

#SPJ12

6 0

1 year ago

What i s the value of a capacitor with 250 V applied and has 500 pC of charge? (a) 200 uF (b) 0.5 pF (c) 500 uF (d) 2 pF

exis [7]

Answer:

(d) 2 pF

Explanation: the charge on capacitor is given by the expression

Q=CV

where Q=charge

C=capacitance

V=voltage across the plate of the capacitor

here we have given Q=500 pF, V=250 volt

using this formula C= $\frac{Q}{V}$

=500× $10^{-12}$ × $\frac{1}{250}$

=2× $10^{-12}$

=2 pF

3 0

3 years ago

Considering the analogy between electrical circuit and thermal circuit, show your approach to derive an expression for the therm

Simora [160]

Answer:

Thermal resistance for a wall depends on the material, the thickness of the wall and the cross-section area.

Explanation:

Current flow and heat flow are very similar when we are talking about 1-dimensional energy transfer. Attached you can see a picture we can use to describe the heat flow between the ends of the wall. First of all, a temperature difference is required to flow heat from one side to the other, just like voltage is required for current flow. You can also see that $R_{th}$ represents the thermal resistance. The next image explains more about the parameters which define the value of the thermal resistances which are the following:

Wall Thickness. More thickness, more thermal resistance.
Material thermal conductivity (unique value for each material). More conductivity, less thermal resistance.
Cross-section Area. More cross-section area, less thermal resistance.

A expression to define the thermal resistance for the wall is as follows: $R_{th} =\frac{l}{Ak}$ , where l is the distance between the tow sides of the wall, that is to say the wall thickness; A is the cross-section area and k is the material conducitivity.

5 0

2 years ago