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3 years ago

A carbon resistor has a resistance of 976 ohms at 0 degrees C. Determine its resistance at 89 degrees C

Engineering

1 answer:

nignag [31]3 years ago

5 0

Answer:

1028.1184 Ohms

Explanation:

<u>Given the following data;</u>

Initial resistance, Ro = 976 Ohms
Initial temperature, T1 = 0°C
Final temperature, T2 = 89°C

Assuming the temperature coefficient of resistance for carbon at 0°C is equal to 0.0006 per degree Celsius.

To find determine its new resistance, we would use the mathematical expression for linear resistivity;

$R_{89} = R_{0} + R_{0}(\alpha T)$

Substituting into the equation, we have;

$R_{89} = 976 + 976*(0.0006*89)$

$R_{89} = 976 + 976*(0.0534)$

$R_{89} = 976 + 52.1184$

$R_{89} = 1028.1184 \ Ohms$

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Answer:

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Explanation:

AB = 1550-Ib ( weight acting on AB )

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169-Ib = weight of man inside cage

Attached is the free hand diagram of the question

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∑ Ma = 0

Ma = 1550 * $x!$ + 190 ( x + 2.5 ) + 169 ( x + 2.5 + 1.75 )

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3 years ago

The idling engines of a landing turbojet produce forward thrust when operating in a normal manner, but they can produce reverse

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Answer:

T = 5416.67 N

T = -2083.5 N

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Forward thrust has positive values and reverse thrust has negative values.

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The thrust force represents the horizontal or x-component of momentum equation:

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$T = flow(m_{exhaust})*(u_{exhaust} - u_{flight} )\\T = (50 kg/s ) * (0 - 41.67)\\\\T = -2083.5 N$

Answer: The thrust force T = -2083.5 N reverse direction

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Answer: T = 0 N

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3 years ago

Water at 15°C is to be discharged from a reservoir at a rate of 18 L/s using two horizontal cast iron pipes connected in series

love history [14]

Answer:

The required pumping head is 1344.55 m and the pumping power is 236.96 kW

Explanation:

The energy equation is equal to:

$\frac{P_{1} }{\gamma } +\frac{V_{1}^{2} }{2g} +z_{1} =\frac{P_{2} }{\gamma } +\frac{V_{2}^{2} }{2g} +z_{2}+h_{i} -h_{pump} , if V_{1} =0,z_{2} =0\\h_{pump} =\frac{V_{2}^{2}}{2} +h_{i}-z_{1}$

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$V_{1} =\frac{Q}{\frac{\pi D^{2} }{4} }$

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The Reynold´s number is:

$Re=\frac{\rho *V*D}{u} =\frac{999.1*6.366*0.06}{1.138x10^{-3} } =335339.4$

$\frac{\epsilon }{D} =\frac{0.00026}{0.06} =0.0043$

Using the graph of Moody, I will select the f value at 0.0043 and 335339.4, as 0.02941

The head of pipe 1 is:

$h_{1} =\frac{V_{1}^{2} }{2g} (k_{L}+\frac{fL}{D} )=\frac{6.366^{2} }{2*9.8} *(0.5+\frac{0.0294*20}{0.06} )=21.3m$

For the pipe 2, the flow velocity is:

$V_{2} =\frac{0.018}{\frac{\pi *0.03^{2} }{4} } =25.46m/s$

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$Re=\frac{\rho *V*D}{u} =\frac{999.1*25.46*0.03}{1.138x10^{-3} } =670573.4$

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The head of pipe 1 is:

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The total head is:

hi = 1326.18 + 21.3 = 1347.48 m

The required pump head is:

$h_{pump} =\frac{25.46^{2} }{2*9.8} +1347.48-36=1344.55m$

The required pumping power is:

$P=Q\rho *g*h_{pump} =0.018*999.1*9.8*1344.55=236965.16W=236.96kW$

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2 years ago

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Mariulka [41]

Answer and Explanation:

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3 years ago

A carbon resistor has a resistance of 976 ohms at 0 degrees C. Determine its resistance at 89 degrees C​

A carbon resistor has a resistance of 976 ohms at 0 degrees C. Determine its resistance at 89 degrees C