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3 years ago

Name eight safety electrical devices including their functions and effects if not present.

Engineering

1 answer:

madam [21]3 years ago

3 0

Answer:

Electricity has two hazards. A thermal hazard occurs when there is electrical overheating. A shock hazard occurs when an electric current passes through a person. Both hazards have already been discussed. Here we will concentrate on systems and devices that prevent electrical hazards. Figure 1 shows the schematic for a simple AC circuit with no safety features. This is not how power is distributed in practice. Modern household and industrial wiring require the three-wire system, shown schematically in Figure 2, which has several safety features. First is the familiar circuit breaker (or fuse) to prevent thermal overload. Second, there is a protective case around the appliance, such as a toaster or refrigerator. The case’s safety feature is that it prevents a person from touching exposed wires and coming into electrical contact with the circuit, helping prevent shocks.

Hope this helps! : )

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3 years ago

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dimaraw [331]

Answer:

The drying time is calculated as shown

Explanation:

Data:

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total moisture of the clay = 0.64

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t = (X0+ Xc)/Rc) + (Xc/Rc)* ln (Xc/X)

= 31.3 min.

4 0

3 years ago

Check Your Understanding: True Stress and Stress A cylindrical specimen of a metal alloy 47.7 mm long and 9.72 mm in diameter is

VARVARA [1.3K]

Answer:

The answer is "583.042533 MPa".

Explanation:

Solve the following for the real state strain 1:

$\varepsilon_{T}=\In \frac{I_{il}}{I_{01}}$

Solve the following for the real stress and pressure for the stable. $\sigma_{r1}=K(\varepsilon_{r1})^{n}$

$K=\frac{\sigma_{r1}}{[\In \frac{I_{il}}{I_{01}}]^n}$

Solve the following for the true state stress and stress2.

$\sigma_{r2}=K(\varepsilon_{r2})^n$

$=\frac{\sigma_{r1}}{[\In \frac{I_{il}}{I_{01}}]^n} \times [\In \frac{I_{i2}}{I_{02}}]^n\\\\=\frac{399 \ MPa}{[In \frac{54.4}{47.7}]^{0.2}} \times [In \frac{57.8}{47.7}]^{0.2}\\\\ =\frac{399 \ MPa}{[ In (1.14046122)]^{0.2}} \times [In (1.21174004)]^{0.2}\\\\ =\frac{399 \ MPa}{[ In (1.02663509)]} \times [In 1.03915873]\\\\=\frac{399 \ MPa}{0.0114161042} \times 0.0166818905\\\\= 399 \ MPa \times 1.46125948\\\\=583.042533\ \ MPa$

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3 years ago

I took my dog for a walk, but he wants to go again.

Talja [164]

He probably just like the cool weather or being outside lol

7 0

3 years ago

Air enters a 28-cm diameter pipe steadily at 200 kPaand 208C with a velocity of 5 m/s. Air is heated as it flows, and leaves the

Alina [70]

Answer:

(a) $\dot V_1$ = 0.308 m³/s

(b) $\dot m$ = 0.732 kg/m³

Explanation:

(a) The volume flow rate is given by the cross sectional area of the pipe × Velocity of flow of air

Diameter of pipe = 28 cm = 0.28 m

The cross sectional area, A, of the pipe = 0.28²/4×π = 0.0616 m²

Volume flow rate = 5 × 0.0616 = 0.308 m³/s

$\dot V_1$ = 0.308 m³/s

(b) From the general gas equation, we have;

p₁v₁ = RT₁ which gives;

p₁/ρ₁ = RT₁

ρ₁ = p₁/(RT₁)

Where:

ρ₁ = Density of the air

p₁ = 200 kPa

T₁ = 20 C =

R = 0.287 kPa·m³/(kg·K)

ρ₁ = 200/(0.287 ×293.15) = 2.377 kg/m³

The mass flow rate = Volume flow rate × Density

The mass flow rate, $\dot m$ = 2.377×0.308 = 0.732 kg/m³

$\dot m$ = 0.732 kg/m³

ρ₂ = p₂/(RT₂)

Where:

p₂ = Pressure at exit = 180 kPa

T₂ = Exit temperature = 40°C = 273.15 + 40 = 313.15 K

∴ ρ₂ = 180/(0.287×313.15) = 2.003 kg/m³

$\dot m$ = ρ₂× $\dot V_2$

$\dot V_2$ = $\dot m$ /ρ₂ = 0.732/2.003 = 0.366 m³/s

$\dot V_2$ = v₂ × A

v₂ = $\dot V_2$ /A = 0.366/0.0616 = 5.94 m/s.

v₂ = 5.94 m/s.

5 0

3 years ago

Name eight safety electrical devices including their functions and effects if not present.​

Name eight safety electrical devices including their functions and effects if not present.