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3 years ago

15

One type of illumination system consists of rows of strip fluorescents and a ceiling that will transmit light. For this system t

o be efficient, the surfaces above the luminous ceiling must be ____.

1 answer:

marshall27 [118]3 years ago

3 0

Answer:

For this system to be efficient, the surfaces above the luminous ceiling must be white, so that all the light been transmitted is reflected.

Explanation:

White surfaces reflect light at almost 100% efficiency, this ensures that non of the light been transmitted is absorbed.

Thus, if one type of illumination system consists of rows of strip fluorescents and a ceiling that will transmit light. For this system to be efficient, the surfaces above the luminous ceiling must be white so that all the light been transmitted is reflected.

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What are the risks of biohacking? Do you think the risks of biohacking outweigh the advantages? Why or why not?

maksim [4K]

Explanation:

Despite its futuristic outlook and results biohacking remains a largely unsupervised, dangerous if not illegal movement. Though the research and results produced by biohackers is ground breaking, it also breaks several ethical codes on human experimentation and endangering live of several humans.

I agree with the fact that risks outweigh advantages, but you can do things like:

- 3D Printing Body Parts

- Finding Cures

- Correcting Deformites.

The only issue is that it's illegal, unfortunately.

5 0

3 years ago

The mechanical advantage of a screw is always ____________________ than/to 1. Question 5 options: less, greater, equal, none of

torisob [31]

Answer:well u can use to make a shelter but that's all I can think of ??

Explanation:

3 0

3 years ago

Five bolts are used in the connection between the axial member and the support. The ultimate shear strength of the bolts is 320

lesya [120]

Answer:

The minimum allowable bolt diameter required to support an applied load of P = 450 kN is 45.7 milimeters.

Explanation:

The complete statement of this question is "Five bolts are used in the connection between the axial member and the support. The ultimate shear strength of the bolts is 320 MPa, and a factor of safety of 4.2 is required with respect to fracture. Determine the minimum allowable bolt diameter required to support an applied load of P = 450 kN"

Each bolt is subjected to shear forces. In this case, safety factor is the ratio of the ultimate shear strength to maximum allowable shear stress. That is to say:

$n = \frac{S_{uts}}{\tau_{max}}$

Where:

$n$ - Safety factor, dimensionless.

$S_{uts}$ - Ultimate shear strength, measured in pascals.

$\tau_{max}$ - Maximum allowable shear stress, measured in pascals.

The maximum allowable shear stress is consequently cleared and computed: ( $n = 4.2$ , $S_{uts} = 320\times 10^{6}\,Pa$ )

$\tau_{max} = \frac{S_{uts}}{n}$

$\tau_{max} = \frac{320\times 10^{6}\,Pa}{4.2}$

$\tau_{max} = 76.190\times 10^{6}\,Pa$

Since each bolt has a circular cross section area and assuming the shear stress is not distributed uniformly, shear stress is calculated by:

$\tau_{max} = \frac{4}{3} \cdot \frac{V}{A}$

Where:

$\tau_{max}$ - Maximum allowable shear stress, measured in pascals.

$V$ - Shear force, measured in kilonewtons.

$A$ - Cross section area, measured in square meters.

As connection consist on five bolts, shear force is equal to a fifth of the applied load. That is:

$V = \frac{P}{5}$

$V = \frac{450\,kN}{5}$

$V = 90\,kN$

The minimum allowable cross section area is cleared in the shearing stress equation:

$A = \frac{4}{3}\cdot \frac{V}{\tau_{max}}$

If $V = 90\,kN$ and $\tau_{max} = 76.190\times 10^{3}\,kPa$ , the minimum allowable cross section area is:

$A = \frac{4}{3} \cdot \frac{90\,kN}{76.190\times 10^{3}\,kPa}$

$A = 1.640\times 10^{-3}\,m^{2}$

The minimum allowable cross section area can be determined in terms of minimum allowable bolt diameter by means of this expression:

$A = \frac{\pi}{4}\cdot D^{2}$

The diameter is now cleared and computed:

$D = \sqrt{\frac{4}{\pi}\cdot A}$

$D =\sqrt{\frac{4}{\pi}\cdot (1.640\times 10^{-3}\,m^{2})$

$D = 0.0457\,m$

$D = 45.7\,mm$

The minimum allowable bolt diameter required to support an applied load of P = 450 kN is 45.7 milimeters.

5 0

3 years ago

Multiply. Write the answer in simplest form. 1 3/10×1/8

kicyunya [14]

9514 1404 393

Answer:

13/80

Explanation:

The product is ...

(1 3/10)×(1/8) = (13/10)×(1/8) = (13×1)/(10×8) = 13/80

4 0

2 years ago

List the main activities of exploration??

Trava [24]

Answer: Exploration includes plethora of activities and depend upon the kind of exploration a person is doing. But most include some of the basic activities like research , investigation, planning and execution.

Suppose we want to explore new petroleum sites then we would have to start with studying the geography of that area, then according to our research we will analyse the hot spots or the sector where probability of finding of oil field is highest, post that appropriate man power is skilled professionals, tools and machinery will be brought at the site so that execution can take place.

3 0

3 years ago