Recent content by Reefy
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Modes of Vibration of 3-DOF Spring Mass System
Something seems off about that because if I say A = 1, then $$A(1-ω^2) - B = 0 $$ $$→$$ $$B=(1-ω^2)$$ And $$C(1-ω^2) - B = 0$$ $$→$$ $$C = B/(1-ω^2) = (1-ω^2)/(1-ω^2) = 1 $$ But I still have the equation for $$B(2-ω^2) - A - C = B(2-ω^2) - 2 = 0$$ $$→$$ $$B=2/(2-ω^2)$$ which will give me...- Reefy
- Post #6
- Forum: Engineering and Comp Sci Homework Help
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Modes of Vibration of 3-DOF Spring Mass System
Ok, if I do that then I get A = C = 1, and then B will equal 1, 0, and -2 for the three different ω- Reefy
- Post #5
- Forum: Engineering and Comp Sci Homework Help
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Modes of Vibration of 3-DOF Spring Mass System
Is there another method that you know of? Can I set up a ratio of the amplitudes? My equations after assuming a solution of X1,2,3 = Asinωt, Bsinωt, and Csinωt are $$ A(1-ω^2) - B = 0$$ $$ B(2-ω^2) - A - C = 0 $$ $$ C(1-ω^2) - B = 0 $$- Reefy
- Post #3
- Forum: Engineering and Comp Sci Homework Help
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Modes of Vibration of 3-DOF Spring Mass System
Homework Statement Homework Equations a11 = a21 = a31 = a12 = a13 a22 = a32 = a23 $$ \begin{bmatrix} x_{1} \\ x_{2} \\ x_{3} \end{bmatrix} =ω^2m \begin{bmatrix} a_{11} & a_{12} & a_{13} \\ a_{21} & a_{22} & a_{23} \\ a_{31} & a_{32} & a_{33}...- Reefy
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- Mass Modes Spring Spring mass system System Vibration
- Replies: 6
- Forum: Engineering and Comp Sci Homework Help
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Heat Loss Through a Short Cylinder
Homework Statement A short metal cylinder 145 mm in diameter and 145 mm high at 1045 K is suddenly exposed (all sides exposed) to a room air temperature at 300 K with h=25 W/m².K. Assume that for the metal k=40W/m.K, den=7800 kg/m3 and Cp=c=600 J/kg.K. Estimate (a) the time required for the...- Reefy
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- Cylinder Heat Heat loss Loss Short
- Replies: 1
- Forum: Engineering and Comp Sci Homework Help
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Thermodynamics Gas Mixture - Dew Point Temperature
Am I supposed to use the humidity ratio to solve this? I thought the 0.1 kg/s was the mass flow rate of dry air ω = 0.622 x (Saturated Pressure)/ (Pressure mixture - Saturated Pressure)- Reefy
- Post #4
- Forum: Introductory Physics Homework Help
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Thermodynamics Gas Mixture - Dew Point Temperature
The saturation pressure at that temperature is 9.14 kPa using linear interpolation with the saturation tables. Ok, so the rate given was for the mixture which is the same for all components. For some reason, I was thinking each component might have a different mass flow rate. Then the part I'm...- Reefy
- Post #3
- Forum: Introductory Physics Homework Help
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Thermodynamics Gas Mixture - Dew Point Temperature
Homework Statement Only Number 1, not number 2 Homework Equations Dew Point Temperature T = Saturated Temperated at Vapor Pressure Partial Pressure = (mole fraction) x (Mixture Pressure) The Attempt at a Solution The dew point temperature is only dependent on the pressure of the water...- Reefy
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- Dew point Gas Mixture Point Temperature Thermodynamics
- Replies: 4
- Forum: Introductory Physics Homework Help
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Calculating Armature Torque for 250V DC Motor
Thanks, I see the mistake I was making! It was pretty simple, I must be tired. Appreciate the help again- Reefy
- Post #14
- Forum: Introductory Physics Homework Help
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Calculating Armature Torque for 250V DC Motor
T = PM/ω = EaIa/(2πN)- Reefy
- Post #12
- Forum: Introductory Physics Homework Help
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Calculating Armature Torque for 250V DC Motor
Ooohh. Yeah, its the conceptual idea I don't get. I don't get why we have to use mechanical power instead of electrical- Reefy
- Post #10
- Forum: Introductory Physics Homework Help
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Calculating Armature Torque for 250V DC Motor
That's what I'm unsure of. I know that Pinput - Poutput = the total losses (Copper, iron, friction). And Copper Loss is I2aRa + I2shRsh- Reefy
- Post #8
- Forum: Introductory Physics Homework Help
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Calculating Armature Torque for 250V DC Motor
Ia1 = IL1 - Ish = 25A - 1A = 24A Ia2 = IL2 - Ish = 50A - 1A = 49A- Reefy
- Post #6
- Forum: Introductory Physics Homework Help
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Calculating Armature Torque for 250V DC Motor
Pinput(1) = VtIL1 = (250 V)(25 A) = 6250 A at the first speed and it is Pinput(2) = VtIL2 = (250 V)(50 A) = 12500 A at the 2nd speed- Reefy
- Post #4
- Forum: Introductory Physics Homework Help
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Calculating Armature Torque for 250V DC Motor
I don't know why it says W. It is ohms. The load current is the current supplied by Vt.- Reefy
- Post #3
- Forum: Introductory Physics Homework Help