# Search results

1. ### Reducing Water Pressure (Pipe sizing)

I have a problem at work and unfortunately it has been too long since I have been in a class room for me to reason this one out, never did like fulid mechanics much :). We have filter that is pressurized to approximately 55 psi. Once ever 12min or so this filter purges a volume of ~2L that...
2. ### Algebraic C-Grid Geneartion Airfoil - Matlab

I'm looking to generate a C-grid for an airfoil using Matlab with clustering at the surface and wake region. I've looked at a book called Computational Techniques for Fluid Dynamics Vol. 2 and it does a decent job of explaining it and has a code but the language is in Fortran and I have no...
3. ### Tennis Ball Cannon Pressure & Exit Velocity

I'm designing a tennis ball launcher using compressed air that will hopefully be able to hit a target at some distance away. We wont know the exact distance until the day of the competition, but I was curious if there was some relatively simple equation relating the pressure of the compressed...
4. ### Ratiation Energy problem

Have this HW for a Thermofluids class and I'm a little confused. Problem A) Use small Biot number approximation to derive the energy equation for a small solid sphere of radius "a" which exchanges radiative energy with a large sphere of radius "b". B) If B -> infinity, show the energy...
5. ### Plotting stress tensor in MATLAB, Parametric Surface

First off, I'm not sure if matlab questions go here or not, or if they are even dealt with on this forum. If not more or remove I guess. I am no matlab wiz so this is mind-boggling to me. I am given a state of stress at a critical point of a component and told to plot a 3D parametric surface...
6. ### Boundary conditions for a 4th order beam deflection equation

What would the boundary conditions be for a fourth order differential equation describing the deflection (elastic curve) of a propped cantilever beam with a uniform distributed load applied? i.e. a beam with a built in support on the left and a simple support on the right. I need 4 obviously but...
7. ### A column under thermal stress

I have a problem with a constrained column under thermal stress where I am to find the reaction forces at the supporting ends of the column due to its own weight after being heated. Attached is the problem, equations used, and my solution attempt. I tried to solve for the reaction forces...

Hi Im trying to help a friend of mine out with this problem he has in a solid mechanics class he is taking, but it has been awhile since I took that course so i was hoping you guys could help me help him :) Here is the problem he gave me. in that image p1 p2 and E1 E2 are the...
9. ### Tension Force question

Question: The cable cars in San Francisco are pulled along their tracks by an underground steel cable that moves along at 9.5mph. The cable is driven by large motors at a central power station and extends, via an intricate pulley arrangement, for several miles beneath the city streets. The...
10. ### E=mc^2 question

What is the momentum of a particle whose total energy is four times its rest energy? Give your answer as a multiple of mc. Well the rest energy of an object is E=mc^2 so the total energy for this particle would be E= 4(mc^2) in order to achieve this Energy value the Lorentz factor would...
11. ### Relativistic density

A cube has a density of 2000 kg/m^3 while at rest in the laboratory. What is the cube's density as measured by an experimenter in the laboratory as the cube moves through the laboratory at 90% of the speed of light in a direction perpendicular to one of its faces? It's the dimensions of the...
12. ### Time Dilation homework

A starship Voyages to a distant planet 10 ly away. The explorers stay 1 yr, return at the same speed, and arrive back on earth 26 yr after they left. Assume that the time needed to accelerate and decelerate is negligible. a) What is the speed of the starship? b) How much time has elapsed on...
13. ### Inductance and current

An RLC circuit consists of a 48 ohm resistor, a 200 uF capacitor, and an inductor. The current is 2.5 A rms when the circuit is connected to a 120 V/60 Hz outlet. a. What is the inductance? b. What would be the current if this circuit were used in France, where the outlets are 220 V/50 Hz...
14. ### Resonace frecuency and peak current

For the circuit shown a. What is the resonance frequency? b. At resonance, what is the peak current through the circuit? http://img218.imageshack.us/img218/2971/p56dr3.png [Broken] I solved for resonance frequency knowing that when Xc=XL you get a resonance frequency. my set up was...
15. ### What is the coils inductance?

A coil has a resistance of 2.10 ohms. The potential difference across the coil is 11.6 V at an instant when the current through the coil is 5.00 A and is decreasing at a rate of 36.0 A/s. What is the coils inductance? I thought i could use the equation X=2pi fL to solve for L.. but i am...
16. ### What is the voltage? AC circuit

A 60 Hz power source with a peak voltage of 12.0 V is connected to a resistor. At a particular instant the voltage across the resistor is 10.0 V and decreasing. What is the voltage 1.5ms later. I tried using the equation v= V cos(2 pi ft) v= 12.0V cos(2pi (60Hz)(1.5 X 10^-3s)) v= 10.13...
17. ### Rate at which energy is dissipated

Light bulbs labeled 40W, 60W, and 100W are connected to a 120V/60Hz power line as shown in the figure. What is the rate at which energy is dissipated in each bulb? http://img156.imageshack.us/img156/9584/p41qz1.png [Broken] Well ac circuits has been confusing me. I first though if a light...
18. ### A conducting loop around a magnetic field

A conducting loop around a magnetic field contains two light bulbs. as shown int the figure. The wires connecting the bulbs are ideal. The magnetic field is increasing rapidly. A. Do the bulbs glow? why or why not? B. If they glow, which bulb is brighter? or are they equally bright? explain...
19. ### What current will allow the wire to float ?

What current will allow the wire to "float"? The linked image is a cross section through three long wires with linear mass density 50 g/m. They each carry equal currents in the directions shown. The lower two wires are 4.0 cm apart and are attached to a table. What current I will allow the...
20. ### Electron traveling through two parallel charged plate. What is Magnetic Field?

An electron travels with speed 1.0 X 10^7 m/s between two parallel charged plates. The plates are separated by 1.0 cm and are charged by a 200V battery. What magnetic field strength and direction will allow the electron to pass between the plates without being deflected.? F= qvBsin\theta...
21. ### Current and Potential difference in a circuit

For the circuit shown find the current through and the potential difference across each resistor. i was using the loop rules to make equations i could substitute into each other to solve this.. but i got stuck when i was making the last one for the currents... thus far i have I3= I4+I5 I1=...
22. ### 2 resistors connected in parallel. same two in series what is the current?

When two resistors are connected in parallel across a battery of unknown voltage, one resistor carries a current of 3.2 amps while the second carries a current of 1.8 amps. What current will be supplied by the same battery if these two resistors are connected to it in series? V=IR well the...
23. ### You construct a rectangle that is 6cm by 8cm

The E-field at the center of 4 charges You construct a rectangle that is 6cm by 8cm, and place the following four charges at each corner: 2mC, -4mC, 2mC, -3mC. The 2mC starts at the top left corner and then each is placed around the rectangle in order in a clockwise manner. A) What is the...
24. ### Rod A is a positively charged insulator.

Rod A is a positively charged insulator. Bob C and a second rod B are in contact with each other and made from conducting material. Rod B is fixed, and C is suspended from a wire and free to swing. Briefly describe what happens when A is brought near B. (I would draw a diagram but i cant figure...
25. ### Two uniformly charge spheres are firmly fastened

Two uniformly charge spheres are firmly fastened to and electrically insulated from frictionless pucks on an air table. The charge on sphere 2 is three time the charge on sphere 1. Which force diagram correctly shows the magnitude and direction of the electrostatic forces: Explain <...
26. ### Ayren purchased a 1000W (120V) hair dryer in the USA,

Ayren purchased a 1000W (120V) hair dryer in the USA, and she took it to Europe where the standard voltage is 220V. Assuming that the hair dryer can operate safely at the higher voltage, can you actually use it if the outlet is rated for 15A, or will it draw too much current (How much current)...
27. ### A dielectric is inserted between the plates of a capacitor.

A dielectric is inserted between the plates of a capacitor. The system is charged and the dielectric is removed. The electrostatic energy stored in the capacitor is 1. greater than 2. the same as 3. smaller than it would have been if the dielectric were left in place. U= 1/2 (K)EAd E^2 K=...
28. ### A toy car has a mass of 120g, including two 1.5V batteries connected in series.

A toy car has a mass of 120g, including two 1.5V batteries connected in series. Suppose the motor that drives the car is 80% efficient (i.e., 80% of the electric energy goes to the drive wheels, 20% is dissipated as heat) and that friction and air resistance are negligible. How much charge...
29. ### A proton is released from rest at the positive plate of a parallel-plate capacitor.

A proton is released from rest at the positive plate of a parallel-plate capacitor. It crosses the capacitor and reaches the negative plate with a speed of 50,000 m/s. What will be the proton's final speed if the experiment is repeated with double the amount of charge on each capacitor? I...