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2 years ago

All machines have three fundamental hazards: moving parts, point of operation, and?

Engineering

1 answer:

OlgaM077 [116]2 years ago

3 0

Answer:

All machines have three fundamental hazards: moving parts, point of operation, and the power transmission.

Explanation:

The unit that supplies power to the machine is a critical hazard due to high energy sources being potential fatal if proper protocols are not followed. This is why lockout tagout (LOTO) measures are put in place in order to protect people while they work on equipment.

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Substance Specific Heat (cal/g°C) Specific Heat (J/g°C) water 1.00 4.18 steam 0.96 4.02 alcohol 0.59 2.47 ice 0.50 2.09 wood 0.4

Jobisdone [24]

Answer:

C) 43,2°C

Explanation:

Sensible heat is the amount of thermal energy that is required to change the temperature of an object, the equation for calculating the heat change is given by:

Q=msΔT

where:

Q, heat that has been absorbed or realeased by the substance [J]
m, mass of the substance [g]
s, specific heat capacity [J/g°C]
ΔT, changes in the substance temperature [°C]

To solve the problem, we clear ΔT of the equation and then replace our data:

Q=890 [J],

m=16,6 [g],

s=2,74 [J/g°C]

Q=msΔT.......................ΔT=Q/ms

Δ $T=\frac{890 J}{16,6g*2,47\frac{J}{gC}}=21,7$ °C

As:

ΔT=Tfinal-Tinitial

Tfinal=ΔT+Tinitial

Tfinal=21,7+21,5=43,2°C

The final temperature of the ethanol is 43,2°C.

4 0

4 years ago

In an apartment the interior air temperature is 20°C and exterior air temperatures is 5°C. The wall has inner and outer surface

ELEN [110]

Answer:

20 W/m², 20 W/m², -20 W/m²

Yes, the wall is under steady-state conditions.

Explanation:

Air temperature in room = 20°C

Air temperature outside = 5°C

Wall inner temperature = 16°C

Wall outer temperature = 6°C

Inner heat transfer coefficient = 5 W/m²K

Outer heat transfer coefficient = 20 W/m²K

Heat flux = Concerned heat transfer coefficient × (Difference of the temperatures of the concerned bodies)

q = hΔT

Heat flux from the interior air to the wall = heat transfer coefficient of interior air × (Temperature difference between interior air and exterior wall)

⇒ Heat flux from the interior air to the wall = 5 (20-6) = 20 W/m²

Heat flux from the wall to the exterior air = heat transfer coefficient of exterior air × (Temperature difference between wall and exterior air)

⇒Heat flux from the wall to the exterior air = 20 (6-5) = 20 W/m²

Heat flux from the wall to the interior air = heat transfer coefficient of interior air × (Temperature difference between wall and interior air)

⇒Heat flux from the wall and interior air = 5 (16-20) = -20 W/m²

Here the magnitude of the heat flux are same so the wall is under steady-state conditions.

7 0

3 years ago

Why do automotive technicians need to have good computer skills?

Elden [556K]

Answer:

Just think about the number of computerized functions there are in modern automobiles.

Explanation:

8 0

3 years ago

Time complexity of merge sort

vovangra [49]

Answer:

The correct answer is " $O (n\times Log n)$ ". A further explanation is given below.

Explanation:

Throughout all the three instances (worst, average as well as best), the time complexity including its Merge sort seems to be $O (n\times Log n)$ as the merge form often splits the array into two halves together tends to linear time to combine multiple halves.
As an unsorted array, it needs an equivalent amount of unnecessary capacity. Therefore, large unsorted arrays are not appropriate for having to search.

6 0

3 years ago

A full journal bearing has a shaft diameter of 3.000 in with a unilateral tolerance of -0.0004 in. The l/d ratio is unity. The b

sashaice [31]

Answer:

i) 154°F

ii) 0.0114 mm

iii) 0.075 btu/s

iv) 0.080 in^3/s

Explanation:

i)Determine the average film Temperature

( from Viscosity-temperature chart in US customary units for SAE10 )

at Temp = 154°F

absolute viscosity = 4.25 rev

and ΔT = 2 ( 154 - operating temp ) = 28°F

where : operating temp = 140°F as given in question

also from the chart applying Raimondi and Boyd boundary conditions

ΔT = 29°F hence we can pick 154°F as the average film temperature

ii) Calculate the minimum film thickness

Cmin = Bore diameter - Journal shaft diameter / 2

= 3.003 - 3 / 2 = 0.0015 in

Given that : h₀ / Cmin = 0.76

there h₀ = 0.0015 * 0.76 = 0.0114 mm

iii)Determine the heat loss rate

Also known as power loss ratio ( H ) = ( 2π*w*f*r*N ) / ( 778 *12 )

( 2π * 0.0132 * 675 * 1.5 * 10 ) / ( 9336 )

Heat loss rate = 0.075 btu/s

iv)Calculate lubricant side-flow rate for minimum clearance assembly

Side flow rate = 0.315 * Total volume flow rate

= 0.315 * ( 3.8 * 1.5 * 0.0015 * 10 * 3 )

= 0.080 in^3/s.

6 0

3 years ago