Science Help

25840 Posts - Page 2 of 1292

energy equation and continuity equation mismatch

A pipe is discharging from H=100m to an open atmosphere. The available discharge at inlet is 0.4m3/s 1. The bernauli's equation tells v=sqrt(2*g*H), neglecting any losses in the pipe, v=~44m/s 2. continuity equation tells v=Q/A, say diameter of pipe=0.3m, v=~5.65m/s which is correct?

MATLAB and the command fprintf

Hi guys i'm doing some homeworks for my professor, the homeworks are some MATLAB scripts that consist in creating and running some functions. The professor is requesting that the results obtained must be written in a file using the command fprintf. I have tried to understand the mechanics of the... MATLAB and the command fprintf

Does an undergraduate degree in physics make me a scientist?

I was wondering this because an undergraduate degree in any engineering make them an Engineer

Venturi / Ejector Design to Boost Water Flow using a Pump

I have a water tank fed from a piping system that has very low head in it. As a result flow tends to be low. See sketch below. I am thinking of ways to boost the flow. I already have a centrifugal pump at the site. Could I use its flow to boost the flow from the incoming pipe via a venturi /... Venturi / Ejector Design to Boost Water Flow using a Pump

Work done on an incline plane with friction

You slide a box of books at constant speed up a 30^\circ ramp, applying a force of 210N directed up the slope. The coefficient of sliding friction is 0.18. 1. How much work have you done when the box has risen 2m vertically? 2.What is the mass of the box? I think I... Work done on an incline plane with friction

An observation about relativistic space travel:

I suppose I am not the first to notice this, but if you are going at say, 0.999c you will have shrunk by a factor of about 20 and everything else on the craft. Suppose the spacecraft is 2000 meters long, at 0.999c it will shrink to about 100 meters long. So suppose a person 2 meters tall, 2000... An observation about relativistic space travel:

Why is the internal energy change of free expansion 0?

ΔU=q-w and in a free expansion w=0 and Free expansion is an irreversible process in which a gas expands into an insulated evacuated chamber. Does this mean that free... Why is the internal energy change of free expansion 0?

increase temperature

hello I have a liquid or gas inside a metallic box (eg. stainless steel 5mm thick) how can I increase its temperature without heat convection or conduction?

Equivalent DC-current of an AC-Current

One has to calculate the equivalent DC-current in order to provide the same power on a load like a sine, triangular and square wave current do in average. I know the general formula for the average power of an AC-current is: $p_{average} = \frac{R}{T} \int_0^T i(t)^2 \, dx$ For the... Equivalent DC-current of an AC-Current

Which is the air resistance formula?

I'm trying to solve this ecuation: Y_1=(-m)/2k((T-mg-kv^2)/(T-mg)) I'm having some truble at finding a correct formula to find the air resistance. In my research through Internet I found loads of different formulas but I dont exactly know which is the correct one. In an other discussion on this... Which is the air resistance formula?

Up and down movement of a monitor

I want to know the various mechanisms for up and down movement of a monitor inside the slot of a table. This is used in the training or conference rooms wherein when the monitor has to go down when not in use inside the slot to the bottom of the table and come up by pushing or actuating with any... Up and down movement of a monitor

(Thermo 3D) Power needed to maintain temp

If we have a cube full of water and glass walls, with an external environmental temperature of 20 degrees celsius, what is the power required to maintain an internal temperature of 25 degrees celsius? Assume sides are 50cm. I don't know what to do, I was trying out the P = (kA/L)(Tf-Ti)... (Thermo 3D) Power needed to maintain temp

simulation low frequency ferrite core recieving antenna

Hi everybody i want to simulate, low frequency ferrite core receiving antenna . but i cant find a good and complete software or method to do this. what is your suggestion or experience? thanks for your attention.

Velocity distribution of evaporating water molecules

What is the velocity distribution of evaporating H2O molecules? It can not be Maxwellian.

Energy conservation and wormholes

Okay, so I've had this question on wormholes which seems to have hijacked my mind from some time now, and what better place to bring it out rather than PF? A previous thread containing lots of lengthy posts was made here a few years ago, but I'm not getting a clear-cut answer despite leafing... Energy conservation and wormholes

Energy and Momentum Thought Experiment

Suppose two balls A and B are connected by a compressed massless spring initially, and they are not under any other forces. The spring is then released and the result is observed. Scenario 1: Ball A has the same mass as Ball B. Scenario 1: Ball A has greater mass than Ball B. Define the... Energy and Momentum Thought Experiment

Why does an alpha particle have 40mm range in air?

Hey everyone... so I understand that an alpha particle, being a helium nucleus, is quite a large particle compared to, for example, a beta particle. Due to this, it will encounter a lot more collisions and impart its momentum to other particles of air at a much more rapid rate. Is there... Why does an alpha particle have 40mm range in air?

Paper-based Origami It Runs using unquestionably the Respira

Japan form of art at collapsible printed involved with subjects, that is called origami, has towards state of the art everyday life when it comes to nanotechnology studies. Enhancements version of this historical sculpture involves we all by indicates of experiments associated with Binghamton... Paper-based Origami It Runs using unquestionably the Respira

First Hello

My name is Liam Ryan and I am working in the defense industry and training to be an engineer. I am studying for an HND in mechanical engineering and I thought that joining a forum like this might assist in the, sometimes, head-bending world of physics and maths. I also think it might help in... First Hello

Elliptical (Oval) Gear

Hi, How can ı design a non circular gear? How drawing teeth profiles?