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3 years ago

Which type of fires should you fight with a portable fire extinguisher?

Engineering

1 answer:

Zolol [24]3 years ago

6 0

Answer:

Class A fires

Explanation:

Class A fires are fires caused by ordinary combustibles, like wood. Assuming this is a portable water fire extinguisher, you should never use it on Class B fires or electric fires.

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A window‐mounted air‐conditioning unit (AC) removes energy by heat transfer from a room, and rejects energy by heat transfer to

Arada [10]

Solution :

Given :

The power of the air‐conditioning (AC) unit is , W = 0.434 kW

The coefficient of performance or the COP of the air‐conditioning (AC) unit is given by = 6.22

Therefore he heat removed is given by , $Q_H = 6.22 \times 0.434$

$Q_H = 2.7 \ kW$

Now if the electricity is valued at 0.10 dollar per kW hour, then the operating cost of the air conditioning unit in 24 hours is given by = 0.10 x 2.7 x 24

= 6.48

Therefore the operating cost = $ 6.48 for 24 hours.

3 0

3 years ago

A/an _____________ comes on if one of the dual hydraulic brake systems should fail or, in some vehicles, if the brake fluid is l

jolli1 [7]

Answer: Dash light

Explanation:

A dash light, usually labeled "BRAKE" will illuminated if a braking system fails, or if the brake fluid is low.

3 0

3 years ago

What is the magnitude of the maximum stress that exist at the tip of an internal crack having a radius of curvature of 1.9 x 10-

Hitman42 [59]

Answer:

2800 [MPa]

Explanation:

In fracture mechanics, whenever a crack has the shape of a hole, and the stress is perpendicular to the orientation of such, we can use a simple formula to calculate the maximum stress at the crack tip

$\sigma_{m} = 2 \sigma_{p} (\frac{l_{c}}{r_{c}})^{0.5}$

Where $\sigma_{m}$ is the magnitude of he maximum stress at the tip of the crack, $\sigma_{p}$ is the magnitude of the tensile stress, $l_{c}$ is $1/2$ the length of the internal crack, and $r_{c}$ is the radius of curvature of the crack.

We have:

$r_{c}=1.9*10^{-4} [mm]$

$l_{c}=3.8*10^{-2} [mm]$

$\sigma_{c}=140 [MPa]$

We replace:

$\sigma_{m} = 2*(140 [MPa])*(\frac{\frac{3.8*10^{-2} [mm]}{2}}{1.9*10^{-4} [mm]})^{0.5}$

We get:

$\sigma_{m} = 2*(140 [MPa])*(\frac{\frac{3.8*10^{-2} [mm]}{2}}{1.9*10^{-4} [mm]})^{0.5}=2800 [MPa]$

5 0

3 years ago

________ are written to “maximize” or “minimize” a specific value associated with the product needs in order to define the goal

Anna35 [415]

Answer:

Objective statements.

Explanation:

An objective statement can be defined as a short statement that explicitly states or describes what a person wants exactly or is looking out for in a particular item.

Objective statements are written to “maximize” or “minimize” a specific value associated with the product needs in order to define the goal or aim of the design process.

This ultimately implies that, objective statements are used by various manufacturing industries or companies to explicitly define the minimum or maximum requirements for the production of its goods.

4 0

3 years ago

Read 2 more answers

Air flows through a device such that the stagnation pressure is 0.4 MPa, the stagnation temperature is 400°C, and the velocity i

RoseWind [281]

To solve this problem it is necessary to apply the concepts related to temperature stagnation and adiabatic pressure in a system.

The stagnation temperature can be defined as

$T_0 = T+\frac{V^2}{2c_p}$