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3 years ago

What Number Am I?

Engineering

1 answer:

noname [10]3 years ago

5 0

Answer:

The number is 768

Explanation:

The given parameters of the three digits number are;

The number is a multiple of four, therefore, a factor of the number = 4

The value of the first digit = A prime number larger than 5

The sum of the last two digits > 10

The value of the ones (place value) digit > The tens (place value) digit

Let 'xyz' represent the digits of the three digits number, we have;

x = A prime number digit larger than 5

∴ x = 7

y + z > 10

z > y and z > x

Given that 4 is a factor of the number, we have;

4 is a factor of 'z'

4 is also a factor of yz

Therefore, the digit, z > 7 and z is divisible by 4, therefore, z = 8

y + z = y + 8 > 10

∴ y > 10 - 8

y > 2

The multiples of 4 larger than 728 with the last digit equal to 8 are found using Microsoft Excel and presented as follows;

748, 768, 788

The numbers that have a larger ones place value are; 748 and 768

The sum of the las two digits are therefore, 4 + 8 = 12 and 6 + 8 = 14

The number that has the largest ones place value for the sum of the last two digits is 768

The number is 768

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Mining is an example of this type of business

luda_lava [24]

Answer:

Mining would go under Industry organization.

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4 years ago

Neon is compressed from 100 kPa and 20◦C to 500 kPa in an isothermal compressor. Determine the change in the specific volume and

PIT_PIT [208]

Answer:

The specific volume is reduced in 80 per cent due to isothermal compression.

Specific enthalpy remains constant.

Explanation:

Let suppose that neon behaves ideally, the equation of state for ideal gases is:

$P\cdot V = n\cdot R_{u}\cdot T$

Where:

$P$ - Pressure, measured in kilopascals.

$V$ - Volume, measured in cubic meters.

$n$ - Molar quantity, measured in kilomoles,

$T$ - Temperature, measured in kelvins.

$R_{u}$ - Ideal gas constant, measured in $\frac{kPa\cdot m^{3}}{kmol\cdot K}$ .

On the other hand, the molar quantity ( $n$ ) and specific volume ( $\nu$ ), measured in cubic meter per kilogram, are defined as:

$n = \frac{m}{M}$ and $\nu = \frac{V}{m}$

Where:

$m$ - Mass of neon, measured in kilograms.

$M$ - Molar mass of neon, measured in kilograms per kilomoles.

After replacing in the equation of state, the resulting expression is therefore simplified in term of specific volume:

$P\cdot V = \frac{m}{M}\cdot R_{u}\cdot T$

$P\cdot \nu = \frac{R_{u}\cdot T}{M}$

Since the neon is compressed isothermally, the following relation is constructed herein:

$P_{1}\cdot \nu_{1} = P_{2}\cdot \nu_{2}$

Where:

$P_{1}$ , $P_{2}$ - Initial and final pressure, measured in kilopascals.

$\nu_{1}$ , $\nu_{2}$ - Initial and final specific volume, measured in cubic meters per kilogram.

The change in specific volume is given by the following expression:

$\frac{\nu_{2}}{\nu_{1}} = \frac{P_{1}}{P_{2}}$

Given that $P_{1} = 100\,kPa$ and $P_{2} = 500\,kPa$ , the change in specific volume is:

$\frac{\nu_{2}}{\nu_{1}} = \frac{100\,kPa}{500\,kPa}$

$\frac{\nu_{2}}{\nu_{1}} = \frac{1}{5}$

The specific volume is reduced in 80 per cent due to isothermal compression.

Under the ideal gas supposition, specific enthalpy is only function of temperature, as neon experiments an isothermal process, temperature remains constant and, hence, there is no change in specific enthalpy.

Specific enthalpy remains constant.

8 0

3 years ago

Consider a thermal energy reservoir at 1500 K that can supply heat at a rate of 150,000 kJ/h. Determine the exergy of this suppl

anzhelika [568]

Answer:

33.4KW

Explanation:

Firstly, we calculate the power index in a reversible heat engine which is given as;

n = 1 - T1/T2

T1 = atmospheric temperature 298k

T2 = reservoir temperature 1500k

n = 1 - 298/1500

n = 0.8013

output energy = n × energy input

0.8013×150000 = 120195KJ/hr

Power output = 120195KJ/hr/3600 = 33.4KW

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3 years ago

A series circuit has 4 identical lamps. The potential difference of the energy source is 60V. The total resistance of the lamps

Alexxx [7]

Answer:

$I=3A$

Explanation:

From the question we are told that:

Number of lamps $N=4$

Potential difference $V=60v$

Total Resistance of the lamp is $R= 20ohms$

Generally the equation for Current I is mathematically given by

$I=\frac{V}{R}$

$I=\frac{60}{20}$

$I=3A$

8 0

3 years ago

Briefly discuss if it would be better to operate with pumps in parallel or series and how your answer would change as the steepn

Aleksandr [31]

Answer:

1) In series, the combined head will move from point 1 to point 2 in theory. However, practically speaking, the combined head and flow rate will move along the system curve to point 3.

2) In parallel, the combined head and volume flow will move along the system curve from point 1 to point 3.

Explanation:

1) Pump in series:

When two or more pumps are connected in series, their resulting pump performance curve will be obtained by adding their respective heads at the same flow rate as shown in the first diagram attached.

In the first diagram, we have 3 curves namely:

- system curve

- single pump curve

- 2 pump in series curve

Also, we have points labeled 1, 2 and 3.

- Point 1 represents the point that the system operates with one pump running.

- Point 2 represents the point where the head of two identical pumps connected in series is twice the head of a single pump flowing at the same rate.

- Point 3 is the point where the system is operating when both pumps are running.

Now, since the flowrate is constant, the combined head will move from point 1 to point 2 in theory. However, practically speaking, the combined head and flow rate will move along the system curve to point 3.

2) Pump in parallel:

When two or more pumps are connected in parallel, their resulting pump performance curve will be obtained by adding their respective flow rates at same head as shown in the second diagram attached.

In the second diagram, we have 3 curves namely:

- system curve

- single pump curve

- 2 pump in series curve

Also, we have points labeled 1, 2 and 3

- Point 1 represents the point that the system operates with one pump running.

- Point 2 represents the point where the flow rate of two identical pumps connected in series is twice the flow rate of a single pump.

- Point 3 is the point where the system is operating when both pumps are running.

In this case, the combined head and volume flow will move along the system curve from point 1 to point 3.

5 0

3 years ago