# Search results

1. ### RK4 for Spring System

I'm not sure if this is the appropriate place, but I've just been searching, with no luck, on how to solve a spring system with RK4 (hence the math section, since it's a Runge Kutta question). How would you set it up to change position based on spring properties? I haven't really found any...
2. ### Blasius Model in Matlab

1. Homework Statement Program, without any built in functions (like ODE45), a solution to the Blasius Equation in Matlab that outputs boundary layer profiles for given x values, u values, etc. 2. Homework Equations 2f''' + f''f = 0 fj = fj-1 + Δη/2 * (gj + gj-1) gj = [Δη2/4][2gj+1/Δη2 +...
3. ### Engineering Feedback Control: Modeling Mechanical System with Circuit

1. Homework Statement Find the transfer function for the following mechanical system with force input fin and output x2. 2. Homework Equations 3. The Attempt at a Solution The reason I left the equations blank is because I'm not sure how to appropriately model this scenario. I've seen two...
4. ### Simple Electrical Modeling Question (w/ only C and L)

1. Homework Statement Find a differential equation that describes the circuit that includes only vin and vout as variables. 2. Homework Equations C(dvin - dvout)/dt = i vin - vout = L(di/dt) 3. The Attempt at a Solution So the answer I got was: C(d2vout/dt2) + vout = LC(d2vin/dt2) My...
5. ### Determine force of water on plate

1. Homework Statement As water flows through the pipe at a velocity of 5 m/s, it encounters the orifice plate, which has a hole in its center. The pressure at A is 255 kPa , and at B it is 180 kPa, Assume water is ideal fluid, that is, incompressible and frictionless. Determine the force the...
6. ### [Fluids] Determine pressure change from industrial jet pump

1. Homework Statement The apparatus or "jet pump" used in an industrial plant is constructed by placing the tube within the pipe. The velocity of the flow within the 200-mm-diameter pipe is 2 m/s, and the velocity of the flow through the 20-mm-diameter tube is V = 37 m/s . The fluid is ethyl...
7. ### Determine force from flow on diffuser

1. Homework Statement Water exits the 3-in.-diameter pipe at a velocity of 12 ft/s and is split by the wedge diffuser. Assume water is ideal fluid, that is, incompressible and frictionless. Determine the force the flow exerts on the diffuser. Take θ = 30 ∘ 2. Homework Equations F = ρAV 3...
8. ### What am I doing wrong in this simple pressure calc?

I'm trying to find gauge pressure at multiple points in a "mixed" container. Which, I thought would be equal to ρghliquid 1 + ρghliquid 2 etc. Well, that's not right? And I don't know why? So for point A, I did: (55.1 * 32.1 * 4) + (62.4 *32.1 * 4). Then I divided by 144 to get it into psi. I...
9. ### Determing the equation of a streamline

1. Homework Statement A fluid has velocity components of u=[30/(2x+1)]m/s and v=(2ty)m/s,where x and y are in meters and t is in seconds. Determine the equation of the streamline that passes through point (2 m, 6 m) at time t = 2 s. Write the equation in the form y={y(x)}m, where x is in...
10. ### If you have a mixture, can you use a saturated liquid table?

I'm working on a problem and need to find quality, mass, and pressure. I'm given a temperature (2°C), a volume (1200m^3), and a percent volume occupation (1% saturated liquid). Is it "legal" to use the saturated liquid tables, at 2°C, to find the volume or pressure (I forget which one we were...
11. ### Fluid Dynamic Torque [in symbols]

1. Homework Statement The conical bearing is placed in a lubricating Newtonian fluid having a viscosity μ. Determine the torque T required to rotate the bearing with a constant angular velocity of ω. Assume the velocity profile along the thickness t of the fluid is linear. 2. Homework...
12. ### Finding stresses at a point

So I'm studying for an upcoming Mechanics of Materials exam. Gotta ace it! Anyways, I'm having trouble with these types of problems. Finding state of stress on a point in 3D. This picture comes from: http://www.academia.edu/6204133/Chapter_09 Which has worn shown, but not explanations. I have...
13. ### Average power dissipated in resistor

1. Homework Statement Find the average power dissipated in the 30 Ω resistor in the circuit seen in the figure if ig=7cos20,000tA. 2. Homework Equations KVL/KCL equations P=VI* (possibly) or I^2(R) 3. The Attempt at a Solution I tried to do a mesh, but got I∆(60-j130) = 0, which isn't right...

1. Homework Statement (in picture) 2. Homework Equations V=IZ 3. The Attempt at a Solution So last time I had to do KCL to find voltages, so I want to make sure I'm doing this one right. Can I do voltage division and do Vload/VG? My division would be VG(500<36.87)/(500<36.87 + 60<53.13)...
15. ### Find transformer primary and secondary voltage/current

1. Homework Statement (in picture) 2. Homework Equations V=IZ All the ratio formulas (i.e. V2/V1 = N2/N1) 3. The Attempt at a Solution I thought V1 would be 1000 Vrms. Well the answers are shown and it's not. So I thought maybe I would multiply Vrms (1000) by root 2 to find Vpeak (Vrms =...
16. ### Engineering Finding the steady state expression of a circuit

1. Homework Statement For the circuit in (Figure 1) , suppose va=10cos16,000tV vb=20cos4000tV. Suppose that R = 700Ω . Write the steady-state expression for io(t) as io=I′ocos(ω′t+ϕ′)+I′′ocos(ω′′t+ϕ′′), where −180∘<ϕ′≤180∘, −180∘<ϕ′′≤180∘, and ω′>ω′′. Find the numerical value of I′o. Find...
17. ### Quick stress calculation with one force on an I-Beam

1. Homework Statement Determine the state of stress at point A on the cross section of the beam at section a−a. TakeP = 33kN . 2. Homework Equations σ = My/I 3. The Attempt at a Solution Moment = Fd = 33000N(500mm) = 165000000 Y = 90.71 (100-9.29, 9.29 being the Ybar of the little piece) I...
18. ### Determining the state of stress at a point

1. Homework Statement Determine the state of stress at point A on the cross section at section a−a of the cantilever beam. Take P = 350kN . 2. Homework Equations Um . . . σ = P/A ? 3. The Attempt at a Solution Yeah I'm not quite sure. I thought it was P/A, using 350000N as "P" and...
19. ### Voltage/Current Division with central Voltage Source

1. Homework Statement Find V0 using voltage/current division 2. Homework Equations V=(VsR)/Req I=(IsIeq)/I 3. The Attempt at a Solution I used general circuit rules (parallel and series) to get the total resistance as 14.775 ohms{?}. And I'm stuck with what to do next . . .
20. ### Finding Water Pressure

1. Homework Statement The following shows a cross section through a tank with a rectangular sloping gate that is 10 m long and 4 m wide (width is measured into the page). The gate is hinged along its top edge and held closed by a force at its bottom edge at A that acts perpendicular to Gate AB...
21. ### Finding Centroids

1. Homework Statement Determine the product of inertia of this area with respect to the centroidal x′ and y′ axes. Locate the centroid x bar of the beam's cross-sectional area. Set a = 120mm , b = 290mm , d = 30mm , h = 390mm . 2. Homework Equations ??? 3. The Attempt at a Solution So I...
22. ### Question about Inductors and Switches

1. Homework Statement The switch has been open for a very long time, and then we close it. In the instant right after we close the switch, assuming that...
23. ### Rotating Bar in uniform B Field

1. Homework Statement A 1.60 m long rod rotates about an axis through one end and perpendicular to the rod, with a rotational frequency of 6.91 radians per second. The plane of rotation of the rod is perpendicular to a uniform magnetic field of 0.30 T. Calculate the magnitude of the mf induced...
24. ### Circuit Segment (Two sources with a resistor in between)

1. Homework Statement If a current I=4 A exists between points a and b, R1=6 http://loncapa.mines.edu/adm/jsMath/fonts/cmr10/alpha/100/char0A.png, [Broken] R2=6 [PLAIN][PLAIN]http://loncapa.mines.edu/adm/jsMath/fonts/cmr10/alpha/100/char0A.png, [Broken] V1=16 V, and V2=6 V,the voltage...
25. ### Low Pass Filter Signal Gain

1. Homework Statement The schematic shows a low-pass filter identical to the one you built in studio. This filter uses a 60 k resistor and a 250 pF capacitor, and the input signal is at 30 kHz. (1 pF=10−12 F)...
26. ### Action Potential Through Ion Channel, Total Number of Ions Through

1. Homework Statement Nerve signals in the body occur when a small voltage, called an action potential, is applied across the membrane of a cell. When this action potential is applied across a region of the cell membrane called an ion channel, current in the form of moving potassium ions will...
27. ### Changing Rho, Finding Resistance

1. Homework Statement A wire with cross-sectional radius 0.91 mm lying along the x axis from x=0 to x=0http://loncapa.mines.edu/adm/jsMath/fonts/cmmi10/alpha/100/char3A.png90 [Broken] m is made of an alloy that varies with its length in such a way that the resistivity is given by...
28. ### Converting one coordinate to full Cartesian/Cylindrical/Spherical

1. Homework Statement Convert to the two other coordinate systems: θ = π/4 2. Homework Equations tan = x/y r = √(x^{}2 + (y^{}2) 3. The Attempt at a Solution The tangent equals one, so doesn't this make just the line x = y? But the cylinder (I'm assuming since the second part is the same...
29. ### Finding Projection of Force onto line

1. Homework Statement Determine the magnitude of the projection of force F = 700N along the u axis. 2. Homework Equations Cosθ = (A • B)/(||A|| * ||B||) 3. The Attempt at a Solution I'm guessing I have to use the above equation, but my problem is finding the B vector. A is easy...
30. ### Pulling a rope on a wall, finding gamma

1. Homework Statement Determine coordinate direction angle γ of the resultant force acting at B. 2. Homework Equations Cos\gamma = F\underline{}z/F 3. The Attempt at a Solution The first part was to find magnitude of F\underline{}b. The next part was finding the other...