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3 years ago

Help now please evaluate using the commutative property: 40 (32) (10) (25)

Engineering

1 answer:

Ilia_Sergeevich [38]3 years ago

4 0

Answer:

#See solution for details.

Explanation:

#The commutative property of multiplication tells us that it doesn't matter in what order you multiply numbers. The formula for this property is a * b = b * a:

$40\times32\times10\times 25=320,000\\\\25\times10\times32\times 40=320,000\\\\10\times32\times25\times 40=320,000\\\\32\times25\times40\times 10=320,000$

Hence, the product of the four numbers remains 320,000 irrespective of their order.

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Explain the differences between planned and predictive maintenance.

sveticcg [70]

Answer:

Planned maintenance refers to any scheduled activity carried out to check a machine is working ok and diagnose procedures to fix it if need it. On the other hand, predictive mainteance is all the techniques which help to define if a machine requires or not maintenance activities so far.

Explanation:

Planned maintenance is based on preventive routines to ensure a machine is working in acceptable conditions and at the same time prevent them to change to risky values performing acticities like parts replacement, cleaning, etc. The key of this maintenance is schedule, that is to say, is a maintenance that has to be carried out constantly each certain time. Predictive maintenance is different because it is used to define if a machie needs any kind of inspection or if, on the contrary, the machine can continue operating without any intervention. The good point about predictive maintenance is the capability of telling when a maintenance is required and when is no necessarily required which is ideal to save costs.

7 0

3 years ago

I need your help to answer in the picture plss help me!

Aloiza [94]

this looks like its the different phases of a single cylinder 4 stroke engine what are you doing in the picture or assignment though matching the numbers to the descriptions on the side?

3 0

3 years ago

A rigid tank contains an ideal gas at 40°C that is being stirred by a paddle wheel. The paddle wheel does 240 kJ of work on the

Sergeu [11.5K]

To solve the problem it is necessary to consider the concepts and formulas related to the change of ideal gas entropy.

By definition the entropy change would be defined as

$\Delta S = C_p ln(\frac{T_2}{T_1})-Rln(\frac{P_2}{P_1})$

Using the Boyle equation we have

$\Delta S = C_p ln(\frac{T_2}{T_1})-Rln(\frac{v_1T_2}{v_2T_1})$

Where,

$C_p$ = Specific heat at constant pressure

$T_1$ = Initial temperature of gas

$T_2$ = Final temprature of gas

R = Universal gas constant

$v_1$ = Initial specific Volume of gas

$v_2$ = Final specific volume of gas

According to the statement, it is an isothermal process and the tank is therefore rigid

$T_1 = T_2, v_2=v_1$

The equation would turn out as

$\Delta S = C_p ln1-ln1$

<em>Therefore the entropy change of the ideal gas is 0</em>

Into the surroundings we have that

$\Delta S = \frac{Q}{T}$

Where,

Q = Heat Exchange

T = Temperature in the surrounding

Replacing with our values we have that

$\Delta S = \frac{230kJ}{(30+273)K}$

$\Delta S = 0.76 kJ/K$

<em>Therefore the increase of entropy into the surroundings is 0.76kJ/K</em>

8 0

3 years ago

Write down one metal or alloy that is best suited for each of the following applications:

777dan777 [17]

Answer:

Explanation:

a. Cast iron or Aluminium alloy are typically used. Aluminium is much lighter in weight and it can transfer heat better to the coolant. While Cast Iron is typically stronger and is thus still used by the manufacturers.

b. Copper can be used as a condensing heat exchanger for hot steam due to its optimal thermal properties and its ability to resist corrosion.

c. high-speed steel are perfect for producing drill bits because of its hardness and resistance to heat to an extent. Drill bits tend to produce heat as a result of the friction between it and the material to be drilled.

d. lead can be used as a container for strong acids because of its anti-corrosive properties

e.zinc and copper can be used as fuel in pyrotechnics mainly due to the fact that burn with refreshing colours. Aluminium can also be used.

f. Platinum is the metal that best suits this purpose because of its high melting point and resistivity to oxidation.

6 0

3 years ago

A 600-MW steam power plant, which is cooled by a nearby river, has a thermal efficiency of 54 percent. Determine the rate of hea

Gennadij [26K]

Answer:

$\dot Q _{L} = 511.111 MW$ . Heat transfer can be higher if themal efficiency is lower.

Explanation:

The heat transfer rate to the river water is calculated by this expression:

$\dot Q_{L} = \dot Q_{H} - \dot W$

$\dot Q_{L} = (\frac{1}{\eta_{th}}-1 )\cdot \dot W\\\dot Q_{L} = (\frac{1}{0.54}-1)\cdot (600 MW)\\\dot Q _{L} = 511.111 MW$

The actual heat transfer can be higher if the steam power plant reports an thermal efficiency lower than expected.

8 0

3 years ago