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2 years ago

Luis is installing some 12 gage wire. How much resistance will there be throughout a distance of 400 feet

Engineering

2 answers:

VLD [36.1K]2 years ago

5 0

I don't know at this point i'm just hungry for points lol

garri49 [273]2 years ago

4 0

Answer:

0.635 m

Explanation:

When calculating the resistance R of a wire, we need its length(l), its cross-sectional area (A) and the resistivity of the material(ρ). The resistance of a wire is given by the equation:

Resistance (R) = Resistivity(ρ) × length (l) / cross-sectional area (A)

For a 12 guage wire,

Resistivity (ρ) = 1.724 × 10 ⁻⁸ ohm m, length (l) = 400 ft = 121.92 m,

Diameter (d) = 0.00205232, cross-sectional area (A) = πd²/4 = π(0.00205232)²/4 = 3.31 × 10 ⁻⁶ m²

$R=\frac{\rho l}{A}=\frac{1.724*10^{-8}*121.92}{3.31*10^{-6}} =0.635m$

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To unload a bound stack of plywood from a truck, the driver first tilts the bed of the truck and then accelerates from rest. Kno

azamat

Answer:

a) The truck must have an acceleration of at least 3.92 * cos(θ)^2 for the stack to start sliding.

b) a = 2.94 * cos(θ)^2 + 0.32 * L * cos(θ)

Explanation:

The stack of plywood has a certain mass. The weight will depend on that mass.

w = m * g

There will be a normal reaction between the stack and the bed of the truck, this will be:

nr = -m * g * cos(θ)

Being θ the tilt angle of the bed.

The static friction force will be:

ffs = - m * g * cos(θ) * fJK

The dynamic friction force will be:

ffd = - m * g * cos(θ) * fik

These forces would produce accelerations

affs = -g * cos(θ) * fJK

affd = -g * cos(θ) * fik

affs = -9.81 * cos(θ) * 0.4 = -3.92 * cos(θ)

affd = -9.81 * cos(θ) * 0.3 = -2.94 * cos(θ)

These accelerations oppose to movement and must be overcome by another acceleration to move the stack.

The acceleration of the truck is horizontal, the horizontal component of these friction forces is:

affs = -3.92 * cos(θ)^2

affd = -2.94 * cos(θ)^2

The truck must have an acceleration of at least 3.92 * cos(θ)^2 for the stack to start sliding.

Assuming the bed has a lenght L.

The horizontal movement will be over a distance cos(θ) * L because L is tilted.

Movement under constant acceleration:

X(t) = X0 + V0 * t + 1/2 * a * t^2

In this case X0 = 0, V0 = 0, and a will be the sum of the friction force minus the acceleration of the truck.

If we set the frame of reference with the origin on the initial position of the stack and the positive X axis pointing backwards, the acceleration of the truck will now be negative and the dynamic friction acceleration positive.

L * cos(θ) = 1/2 * (2.94 * cos(θ)^2 - a) * 0.4^2

2.94 * cos(θ)^2 - a = 2 * 0.16 * L * cos(θ)

a = 2.94 * cos(θ)^2 + 0.32 * L * cos(θ)

6 0

2 years ago

An overpass is being built over the PVI of an existing equal-tangent sag curve. The sag curve has a 70 mi/h design speed and G1=

vivado [14]

Answer: Resultant elevation will be 30.98 ft

8 0

2 years ago

A 75,000 ft3 clarifier is to be used to treat wastewater. The recycle ratio is 50%, the sludge volume index (SVI) is 125, and th

Inessa05 [86]

Answer:

11 hours approximately

Explanation:

We are to calculate mean cell residence time mcrt

= Mass of solid in reactor/mass of solid wasted in a day

Q = Qe + We

Q = 2.5

Qw = 0.5

Qe = 2.5 - 0.5

= 2 MGD

10⁶/svi

= 10⁶/125

= 8000

X = 3500

Xe = 20mg/

1MGD = 0.1337million

Mcrt = 75000x3500/[0.5*8000*10⁶+2*20*10⁶] x 0.1337

= 262500000/[4000000000+40000000} x 0.1337

= 262500000/574800000

= 0.45668 days

= 0.45668 x 24 hours

= 10.9603 hours

Approximately 11 hours

3 0

2 years ago

An inventor claims to have devised a cyclical engine for use in space vehicles that operates with a nuclear fuel generated energ

slava [35]

Answer:

Inventor claim is not valid.

Explanation:

Given that

Source temperature = 510 K

Sink temperature = 270 K

Power produce = 4.1 KW

Heat reject = 15,000 KJ/h

Heat reject =4.16 KW

As we know that

Heat addition = Heat rejection + Power produce

Heat addition = 4.16 + 4.1 KW

Heat addition = 8.16 KW

So efficiency of engine

$\eta =\dfrac{Power\ produces}{heat\ added}$

$\eta =\dfrac{4.1}{8.16}$

$\eta =0.502$

Now check the maximum efficiency can be possible by using Carnot heat engine

As we know that efficiency of Carnot heat engine given as

$\eta =1-\dfrac{T_L}{T_H}$

By putting the value

$\eta =1-\dfrac{T_L}{T_H}$

$\eta =1-\dfrac{270}{510}$

$\eta =0.47$

So the efficiency of Carnot cycle is less than the efficiency of above given engine.So this engine is not possible.It means that inventor claim is not valid.

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2 years ago

A non-licensed person may be the SOLE owner of a civil, electrical, or mechanical engineering business under which of the follow

kotegsom [21]

Answer:

(d) None. No provisions exist.

Explanation:

B&P Code § 6738 prohibits a non-licensed person from being the sole proprietor of an engineering business. The non-licensed can be a partner in an engineering business that offers civil, electrical, or mechanical services. It is mandatory that at least one licensed engineer must be a co-owner of the business.

5 0

2 years ago