# Search results

1. ### Calculation of magnetic force on a wire

What I am really trying to do is move a length of wire along a duct, from outside the duct. I will be doing it experimentally. However, it would help if I could calculate the strength of the magnet I would need rather than trying to guess and do it by trial and error.
2. ### Calculation of magnetic force on a wire

Hi, I would like to know if it is possible to move a steel wire against frictional forces using a magnet. What would be the approach of calculating the force acting on that thin wire. I would know the dimensions of the wire and the dimensions of the magnet. What other values should I find...
3. ### Voltage. What is it really?

I think the box being pushed analogy makes the most sense. I passed through school and then college without ever realizing how cool this analogy was. Drakkith gave a great thing to remember about voltage!!
4. ### A Question on Fluid Pressure

Hi TheMak, Both the fluids are flowing at the same mass flow rate. As fluid properties are also the same, the volumetric flow rate may also be considered to be equal. As the pipes have different cross sectional areas, the fluid velocities would be different. Pipe A with the smaller cross...
5. ### WHat is the uncertainty in a metre rule?

This method of uncertainty calculation is correct, but it holds for calculating the uncertainty when using different rulers (sensors in general). In this case, the maximum uncertainty is 1mm. This is because in the first reading you could be off by -0.5 mm and in the second reading it could be...
6. ### Experimental Fluid Mechanics Videos Series

An invaluable source. Really great. I have enjoyed a good few of them, and keep referring other people to go to the page or share the videos. They are just awesome. Thanks for sharing them.
7. ### De - Ionized (DI) Water

Thanks for the insight. The replies have all helped a lot. I understand that it is highly pure form of water. And it is quite corrosive too due to the attraction it shows to ions in whichever container it is kept in. I am keeping my DI water in plastic containers. I was hoping for a time scale...
8. ### De - Ionized (DI) Water

Hi, How long does de-ionized water remain de-ionized. After what amount of time would it start geting ionized again. I understand that it would greatly depend on the container in which it is kept and the environmental conditions. However, the order of the time would help me. Thanks.
9. ### Finding the right Tires

Another likely option if you wanted slightly higher speeds would be the motorcycle wheels with spokes. They are much lighter than car wheels and perform nicely for light weight vehicles. This is only if you want to attain higher speeds. For low speeds, the cycle tires should do fine.
10. ### Variable pressure

I am working on an experiment where i would like to see how the system responds to pressure fluctuations. I tried using a stepper motor and a cam arrangement to create pulses in the pipe carrying water to the system. However, I can't get higher frequencies of pressure oscillations. I have...
11. ### Depth of mirror

I'm feeling tempted to build it too!!
12. ### CATIA eBooks

the first link is an extract from the User Guide. Very helpful. The second link is dead. But thanks a lot for the links. It was a lot of help
13. ### Variable pressure

I need to introduce variable pressure into a system. I was planning on using piston pumps which if i run at low rpms would result in controlled fluctuating pressures. Am i doing something wrong?
14. ### Humidity and its effect on air properties

Hi, I would like to find the properties of humid air at different humidities and different temperatures. What sort of charts should i consult? I tried looking at psychrometric charts, i'm not sure if i'm reading the correct thing. Thanks
15. ### Pressure Temperature Relation

I can not assume it to be compressible fluid. So the ideal gas law is ruled out. I mean the pressure (volume) and temperature.
16. ### Pressure Temperature Relation

Is there a relation between pressure/velocity and temperature for liquids. Something like the ideal gas law for fluids in general?
17. ### Renewable Energy (Gravitation)

You can use gravity in the form of a waterfall. But you can't make a stand alone system without the waterfall. That would mean an endless cycle with only energy output. You are defying the first law of thermodynamics.
18. ### Calculating the hydrodynamic entry length of a cicular pipe.

I'm looking for the same solution for 2D channel flow. Can someone help me? I need the derivation
19. ### Vapor Quality calculation

now there is a change in the calculations i need to perform. I have the heat flux and the mass flow rate. How should i go about calculating the vapor quality. I couldn't remember the formula, so thought of asking here.
20. ### Vapor Quality calculation

Thank you Q, That was helpful. -Rupak
21. ### Vapor Quality calculation

Water is being used as a coolant by flowing through a channel. I know the mass flow rate of water. And i know the inlet properties of water. I also know that the water is coming out of the channel at a vapor quality of 1. How do i calculate the heat flux that the water is subjected to during...
22. ### Earth Gravitation problem

As soon as you put another large mass into the system, you have to consider the shifting of the centre of mass. The earth will exert a pull on this body and this body will exert a force of attraction on the earth. The centre of mass will shift according to the mass of this new body in space and...
23. ### Simple Harmonic Motion. Why is Acceleration proportional to NEGATIVE displacement?

acceleration and displacement are vectors. they have direction. the acceleration is opposite in direction to the displacement and tries to bring it back. hence the minus sign to signify that the two vectors are opposite in direction.
24. ### Does the viscosity of air change with change in the degree of humidity

Does the viscosity of air change with change in the degree of humidity at room temperature?
25. ### Flow development

I found the solution ..so here it is.... for a flow to be fully developed, it should have no change in the u component. i.e. du/dx = 0
26. ### Flow development

Homework Statement The following stream function holds for a certain flow of water at 20 C. psi = 4y - (y^3)/3. Is this flow fully developed? Homework Equations psi = 4y - (y^3)/3. The Attempt at a Solution How am i suppose to tell if a flow is fully developed or not from...
27. ### Rotation of flows

Yes i wrote the question out exactly as it was given to me.
28. ### Rotation of flows

Homework Statement If liquid contained within a closed circular cylinder rotates about the axis of the cylinder, prove that the equation of continuity and boundary conditions are satisfied by V = (omega) x r, where 'omega' is the angular velocity of fluid supposed to be dependent on time only...
29. ### Fully developed flow

Ψ=4y-((1/3) y^3) This is the stream function i'm referring to here.
30. ### Presentation on Permeability

Hi, I'm working on a presentation on Permeability. I need some basic information to start off. However, when i google permeability, all i get is magnetic permeability or permeability of the different types of soils. I'm more interested in the permeability of particles through semi porous...