Compression Definition and 633 Threads

Homework Statement U = u(T)V; P=u(T)/3 a. Find (ds/dt)v and (ds/dv)T in terms of u. Ans. (ds/dt)v = 1/T[du/dt] and (ds/dv)T = 1/T[du/dv + P]...Correct b. Show that u(T) = Const*T^4 equate partials above and integrate...Correct c. Find a Relation between V and T during adiabatic compression or...

Hi all, I am doing a High Velocity Impact testing using a gas gun I have to figure out a) is my test running well and I am not getting any reflection? Please correct me or help in calculating if I am wrong at any point. I guess, I can figure out by calculating the time required for the...

I am doing a experiment with model rockets to see if a added compression nozzle on a model rocket would make the engine perform better. As you can see in this picture there is a small clay nozzle immediate to the propellant. This is the same place that you put the igniter. My experiment is...

Homework Statement A bloc of 0,2 kg is attached to a spring on a horizontal surface with no friction. (The other side of the spring is attached to a wall, so it doesn't move) The spring constant is 5 N/m. If we pull on the spring, we move it by 0,12 m from its natural position and we let it go...

For typical metals used in construction I've seen the compression strength being used in various calculations. Typically I assume this is the uniaxial compressive strength. i.e. Say in a UTM with the specimen laterally loaded. Are there engineering situations where the hydrostatic compressive...

I solved the equilibrium equations and found that link BD is in tension while link CE is in compression, but my resulting answers for normal stress were wrong. The solutions show that the cross area to be used for normal stress at links BD and CE should be different. Link BD should incorporate...

If I have 2 sealed tanks A and B of 1 cu ft volume that contain air at atmospheric pressure and are at 300 deg K. temp absolute. For tank A I raise the temperature from 300K to 600K and I suppose the pressure will double due to this and would be 14.7 * 2 = 29.4psi absolute For tank B I use a...

An inclined plane of angle θ = 20.0° has a spring of force constant k = 525 N/m fastened securely at the bottom so that the spring is parallel to the surface as shown in the figure below. A block of mass m = 2.31 kg is placed on the plane at a distance d = 0.312 m from the spring. From this...

The Problem: A 1.80 mol sample of an ideal gas is compressed isothermally from 58.1 L to 15.6 L using a constant external pressure of 2.72 atm . Calculate W: Calculate Q: Calculate ΔU: Attempt at solution: I tried W = P(ΔV) to no effect, W = nRTln[Vf/Vi] to no effect. The online...

Hi all, I am trying to work out the stress on a shaft when a compressive force is placed on it such as a taper lock or press fit. I have looked at all the thin and thick wall section formulas and they seem ok. I am not sure what happens when the internal radius becomes 0 and its a solid shaft...

Good day, I am trying to calculate the stress along the yy-direction for a 3D object compressed in the zz direction (perpendicular to it). The width of the object (in the yy direction) is constant, and the object can only deform along the xx direction. All stresses except for sigma_zz (known)...

Hi everyone, it's my first post! I need to elevate a bed by 4 inches for a while. I did some work on this problem already. Here's all the information I used to reach my conclusion: expected total weight with mattress and occupants = 220.92200 kilograms bed weight = 54 kg = 54,000 grams =...

How much does a Piezoelectric crystal (say PZT) compress when applied the maximum amount of force it can withstand ? also it would be very helpful if someone could tell me how much is this force typically ?

Hello Is there any fluid other than air which is compressible. http://www.scienceinfusion.com/air-the-fluid/

https://en.wikipedia.org/w/index.php?title=Explosively_pumped_flux_compression_generator&oldid=655971586 This technology according to what I've been reading has extremely powerful energy and I'm wondering what technologies it's used for today. Has there been propulsion systems made with this...

I was wondering what would happen if you were to have two really strong repelling magnets that were being forced together by a sphere of let's say solid copper mesh and then spun the magnets or sphere or both at a really high rpm. Or just a really strong compressed magnetic field however the...

1.what is the work done in an adiabatic compression process in a carnot cyclewhen we consider work done in efficiency why do we take heat exchange into account i.e.,qs-qrThe Attempt at a Solution

Homework Statement A 0.60kg cart moving at 5.0m/s[W] collides with a 0.80kg cart moving at 2.0m/s[E]. The collision is cushioned by a spring(k=1200N/m). Homework Equations [W] is Positive PTo=PTf ETo=ETf The Attempt at a Solution PTo=PTf m1v1o+m2v2o=(m1+m2)vf...

A manufacturer quotes a standard CO2 canister contains 16g of CO2 at a volume of 20cm^3. So I need to calculate the pressure in the canister... Using ideal gas law P = nRT/V n = 0.364mol (16 of co2) R = 8.314 J/Kmol (universal gas constant) T = 294k (gas is at room temp 21 deg C) V = 20cm3...

There are claims or at least assumptions that: "upon approaching "critical point" pure gases become super compressible. You could compress them many times without pressure increase and store like this if you maintain exact temperature and pressure needed. It opens possibility to superdense gas...

I am trying to find the theoretical power required to compress nitrogen from a pressure P1 to P2, as well as the final temperature T2 after compression. I found no formula that were anywhere near complete, but I found this tool, which tells me that from 300K@1Bar, I need 271.4kw (271kj/s) to...

Hello and thanks in advance for reading or contributing... In regards to another thread here, https://www.physicsforums.com/threads/sound-as-condensation-or-rarefaction-of-air.817705/ , I am convinced a compression wave would cause an oscillation as it passes your ear. This raises the question...

Can piezoelectric crystals produce electricity from compression only ? When continuous compression and tensile forces on them generate AC voltage source, can only compression force give me a DC voltage source ? Is there a chance that the crystal will initially act as a Voltage source but soon...

When a loudspeaker moves back and forth, sound is generated. The moving of the loudspeaker diaphragm causes condensation of air when it moves outward, and rarefaction of air when it moves inward. When this movement is happening at a certain frequency, we hear a sound. See for example this...

Hi I'm working on a project where I would need to lift about 400 pounds about 1 inch off the ground and keep the momentum in order to manually move it. I thought about using four fans with a skit on each corner facing downward to allow for upward movement, but I'm not sure how much power I would...

Homework Statement Students in a physics class set up an experiment to examine the behavior of springs being compressed under various conditions. In the first trial of the experiment, students released a 1.5 kg block from rest at the top of a ramp. The block slid down the ramp, across a...

Homework Statement Air at 20C is compressed adiabetically from 1 bar to 10 bar. What will its temperature be? Homework Equations pV = nRT, P1P2=T1T2 P1Vλ1=P2V2λ The Attempt at a Solution In picture...[/B]

The question tells us that a tensile force of 80kN acts upon the thin rod and hence we know there will be an equal but opposite force on the other side. However, I don't understand why there are compressive forces on the tube? We aren't told about this in the question. Thanks

Homework Statement A 2kg box traveling at a velocity of 5 m/s hits a spring (k=100 N/cm). Find a. How much the spring will compress b. What is the average force on the spring c. If the surface has μs = 0.15 and μk = 0.12, how far will the box rebound from the spring d. If the surface is...

Hi guys, Bit of a noob engineer here so looking for some guidance. I'm designing a fixture which will be constructed from stainless steel rectangular tube as shown in the diagram. If I apply a 10,000kg weight over a 100mx100mm area how do I go about calculating the stress and ultimately safe...

Homework Statement "A coil spring has a force constant of k = 4.0 lb/in. When the spring's axis is inclined at an angle 30 degrees from the horizontal, a W = 2.0 oz ball is propelled to a height of 6.0 ft. By how much must the spring have been compressed initially? (1 lb = 16 oz) Homework...

Homework Statement Russian aviator Vsevolod Mikhailovich Abramovich invented the Abramovich Flyer based on the design of the Wright brothers' first plane. After this first success, Abramovich became obsessed with deep space travel designing a spring based launcher to fire a probe of mass 90kg...

Here is some background for this post and for future "Curiosity question" posts. So last year in 10th grade, I took AP Calc AB and AP Physics B, and scored 5s on both, but a particularly high five on the physics, as I truly enjoy doing physics just for the bliss of it. Well this year, I stepped...

Dear All, I am a mechanical engineer who has recently started working in the oil& gas industry (compression). I would appreciate if someone can guide me to where can I learn about reciprocating compressors. Much appreciated.

Homework Statement A block of mass m1 slides along a frictionless table to the right with a speed of v1. A second mass M2 slides in the same direction with a speed of v2 such that it will collide with m1 which is in front of m2. Say that a spring of stiffness k is attached to one of the masses...

Homework Statement A box has the mas 50.0Kg. The box slides on a horizontal surface that has friction. The box has the velocity 3.00m/s when its 0.600m away from a spring with negligible mass and the force coefficent 20Kn/m. The box hits the spring and comes to a momentary rest after...

Hi! For our class project, we have to design a system that freezes an amount of water as quick as possible. The refrigerant is R134a. The compressor is known. I don't really know how to get started here. How do I choose the evaporator pressure and the superheating, and equally the condensor...

Hi there, I was wondering if you could help me, I think I may have some concepts wrong or incomplete. Homework Statement We have an adiabatic cylinder of volume ##V_1## filled with a gas of pressure ##p_1## and temperature ##T_1## in thermal equilibrium, closed with a piston. All of a suden...

Hi, I am working on investigating an idea I proposed regarding a ramjet that operates in subsonic flow (of a fixed speed) with a convergent intake. That utilizes the pressure immediately behind a standing shock-wave for compression. I have posted a link to my initial report here and I now need...

This is not a homework problem but rather a passage from my textbook that I don't understand. I don't think I quite understand the concept of reversible processes. Here is the passage from my book: "Consider a system in the quantum state s of energy Es. We assume Es to be a function of the...

Homework Statement This is not a homework problem but rather a passage from my textbook that I don't understand. I don't think I quite understand the concept of reversible processes. Here is the passage from my book: "Consider a system in the quantum state s of energy Es. We assume Es to be a...

When examining a member, how do I tell whether it is undergoing tension or compression? It's more of a general question, but since a visual might help with the explanation, this could be useful:

Homework Statement 10 liters of air at atmospheric pressure and temperature 3000K were isothermally compressed to a volume of 2[liter] and then freely expanded adiabatically to their original volume. what's the final temperature. Homework Equations Adiabatic process...

A convoy of spatial ships leaves the Earth at a speed v. Each ship is relativistically compressed in the direction of movement. What happens to the space between the ships? Is it compressed too?

I'm a student taking a non-calculus strength of materials course, and I believe I have what is probably a very simple misconception. I'm wondering why in the "eccentrically loaded column" b), which has two point loads placed at distances of equal magnitude from a centroidal axis, the moments...

I always thought of a reentry vehicle compressing the air in front of it. And that would cause a lot of heat kind of like filling my tires. But I keep hearing friction even from NASA heat shield experts. OK, I guess maybe 10% of the heat is friction. I always assumed they said that to make the...

Homework Statement You are asked to figure out the force required to coin a 25-cent piece and are given the final dimensions and an average flow stress. Sticking friction is "reasonable" Hosford and Caddell 2nd Ed. Q 7-3 Homework Equations Pa = Y + 2kR0/3h0 The Attempt at a Solution I...

I'd like to learn more about the way energy is stored in a springhttp://en.wikipedia.org/wiki/Spring_(device) . I found this site http://www.leespring.com/int_learn_compression.asp I learned that a 50mm free-length spring can be compressed for 20mm (at most by 40%) to solid length (30mm) and...

Hello PF members and guests, I have been working on this concept for 2 years and I wanted to get some input from this forum. I have done a lot of research on oxygen enriched combustion and water injection. Both of these concepts have been tested and proven in experiments and the real world. My...

If you have a tank with compressed air. Say this tank is a cube of 1x1x1m. One of the walls are "mobile" but sealed so no air can excape. A spring on the outside is pushing on this wall so it will remain in its position at for example 10 bar pressure inside the tank. Now, atmospheric air has a...