Internal Definition and 993 Threads

Homework Statement Two bodies of mass M and m separated by a distance 'R' are released and they move towards each other under the influence of gravity . What is the work done by internal forces (considering the 2 bodies as a system) when they are at a distance 'x' apart ? The Attempt at a...

A battery labeled 12.0 V supplies 1.90 A to a 6.00 ohm resistor A) what is the terminal voltage of the battery? B) What is its internal resistance V = 12.0 R = 6.00 I = 1.90 I think i am to use V = emf - IR for terminal voltage right? however i do not know how to get emf, and IR...

Homework Statement One rechargeable battery of mass 15.0 g delivers to a CD player an average current of 15.5 mA at 1.00 V for 2.50 hr before the battery needs to be recharged. The recharger maintains a potential difference of 2.00 V across the battery and delivers a charging current of 10.0...

Hi all, I read that the internal entropy change of a system (\DeltaSi) for a non-quasistatic process where a reservoir cools or heats the system, where N and V are fixed and no work is done is approximately equal to (\DeltaT)2, when the difference between TReservoir and Tsystem is small. The...

Homework Statement A simple hydrostatic system is such that PV^k is constant in a reversible adiabatic process, where k > 0 is a given constant. Show that its internal energy has the form E=\frac{1}{k-1}PV+NF(\frac{PV^k}{N^k} where f is an arbitrary function. Hint: PV^k must be a function of...

U is internal energy, which is the sum of heat + work done. \DeltaU = q + w -----(1) where w = \Delta(PV) Enthalpy is the internal energy + work done \DeltaH = \DeltaU + P\DeltaV At constant pressure, \DeltaH = q - P\DeltaV + P\DeltaV \DeltaH = q_{p} Where q_{p} is used to...

In my book it says that the change in internal energy = Q -W Yet, my teacher says that its Q + W He says that it's reversible due to the signs... but i don't know what that means... can somebody give me an example?

Homework Statement A moves with momentum p into B at rest. The objects collide and move off with momenta p_1, p_2 at an angle (irrelevant but anyway). What are the internal forces in the system? Homework Equations F=p dot The Attempt at a Solution What's an internal force? Isn't it...

Hi there, I have some serious problems with a couple of questions. Need help for exam revision. 1.1 Homework Statement A 2kg chunck of ice at -10Celsius is added to 5kg of water at 45Celsius. What is the final temperature of the system? 1.2 Relevant equations specific heat capacity of ice -...

Homework Statement Two almost identical lead-acid accumulator batteries, X and Y, are connected with opposing polarities in a circuit which includes an ammeter, an ideal millivoltmeter and a resistor R as shown in figure below. When S1 is closed with S2 left open, the millivoltmeter reads 50...

A small source of light at the bottom face of a rectangular glass slab 2.25 cm thick is viewed from above. Rays of light totally internally reflected at the top of the surface outline a circle of 7.6cm in diameter in the bottom surface. Determine the refraction index of the glass. This is...

Homework Statement My physics teacher (i'm in year 12) set me a "challenge" to prove a graph in our textbook, which shows Power against Resistance, with a local maximum where R = internal resistance, r. He told me i'd need to use differentiation, P = I^{2}.R and said that I was right in...

Homework Statement Suppose 1 g of water vaporizes isobarically at atmosphere pressure (1.013 x 105 Pa). Its volume in the liquid state is Vi = 1 cm3, and its volume in the vapor state is Vf = 1671 cm3. Find the change in internal energyHomework Equations \Delta U = \Delta Q - \Delta W \Delta...

Homework Statement I have been stuck on the following problem for 2 days now, can anyone help? The p.d. at the terminals of a battery is 25V when no load is connected and 24V when a load taking 10A is connected. Determine the internal resistance of the battery... Thanks Homework...

I am very much confused with this statements "The forces of action and reaction never cancels out each other , but the internal forces on a system of particles cancel out in pairs " I think i know the reason for the first statement.i.e,The forces of action and reaction are acting on different...

This looks to be a much more active forum than another I tried to get some feedback on recently...same question, hoping someone here can weigh-in on this before I potentially make a mistake. I'm installing a mini PCI WLAN card (802.11n/g) and antenna inside of a small form-factor PC. The...

Homework Statement Please help with this problem! How many sprints from rest to a speed of 4.5 m/s would a 59 kg woman have to complete in order to burn off 5.0 x 102 Calories? (Assume 100% efficiency in converting food energy to mechanical energy.) Homework Equations...

hello happy new year i'm a little confused here after i saw this U= KE + PE + H(enthalpy)----------------------1 while it is known that H=U+PV------------------2 i'm sure that eqn 2 is true but do you think with m that 1 is not true ?? the problem is that my instructor use...

I’m from a group that is current working on the theory of a Hydrogen Economy. Our first area of development is the Hydrogen Highway. We are currently seeking help in the form of freelance / work for hire basically engineer(s) that could aid in design and calculations of internal combustion...

Hi, I've got a problem with collision detection of which I am struggling to find a solution. In the simplest case, I would have a sphere whose movement would be constrained inside a closed arbitrarily-shaped object. I have been looking into BSP trees which split the shape into chunks...

Homework Statement The drawing shows a crystalline quartz slab with a rectangular cross-section. A ray of light strikes the slab at an incident angle of 1=34o, enters the quartz and travels to point Po (Figure2). This slab is surrounded by a fluid with a refractive index n...

Homework Statement You have a power supply of 10 V. It is connected in series to a 2 ohm resistor and a 5 ohm resistor. You take the voltage across the 5 ohm resistor with a voltmeter that has an internal resistance of 3 ohms. What is the current through the voltmeter?Homework Equations The...

Homework Statement Have to determine permeabilities \alpha and \beta (PNa/PK and PCl/PK) as well as internal concentrations of Na+, K+ and Cl- I have calculated different membrane voltages according to the external concentration (when altering one ion, the other two were set to zero)...

Homework Statement Consider a common mirage formed by superheated air just above a roadway. A truck driver whose eyes are 2.00 m above the road, where n=1.0003 looks forward. She has the illusion of seeing a patch of water ahead on the road, where her line of sight makes an angle of 1.20...

Homework Statement The internal energy of a system increases by 200 J while 900 J of work are performed on it. What was the magnitude of the heat flow into or out of the system? Does the heat flow "out of" or "into" the system? Homework Equations Don't really need. The Attempt...

Hi there, my first post on this forum and I hope its in the right place ! My question is this, in an exisitng air-cooled motorcycle engine what is the viability of using heat pipe technology to cool exhaust gas temperature? Using heat pipes to remove heat from exhaust valve areas to external...

Basically I want to Calculate the internal resistance of a solar cell. I set up a circuit with a voltmeter across the solar cell and an ammeter and variable resistor in series with the solar cell. The variable resistor is the load. Image at...

What is the fastest speed ever recorded, achieved by a internal combustion piston engine on a land vehicle, and not an aircraft/propeller? I know that some top-fuel dragsters can exceed 300 MPH.

I want to tap a NPT (NPT-3/4) thread hole on a plate. And I found some related standards, these standards told me the detailed dimensions of the thread. My question is how to machine the NPT thread with a tap? How to control the parameter mentioned in the standards? thanks in advance!

can anyone please tell me what is the gas pressure which applies on piston head just after combustion in cylinder its very urgent and necessary for me to know this please help me

Homework Statement A monatomic ideal gas expands from 1.00 meters cubed to 2.50 meters cubed at a constant pressure of 2.00 x 10^5 Pa. Find the change in the internal energy of the gas. Homework Equations \DeltaU = Q + W The Attempt at a Solution Well, I know how to find work...

In polytropic process internal energy change is=mCv(T2-T1)? why is it not mCp(T2-T1)? Why are we not taking specific heat at constant pressure?

hi everyone, i am trying to build a very high current dc to ac inverter and i can't use a 555 timer IC because they can't source or sink but a maximum of 200mA, but i have found an internal schematic of the 555 timer IC online and have been studying it to see if i can build a very high current...

Hey all, I know that it is forbidden to post homework questions here, this is a question off a past exam, so I'm hope asking this is Kosher. A question says: "For a circular pipe of 6cm diameter, what is the expected pressure drop per unit length due to frictional losses, at a Reynolds...

Homework Statement A body m1 + m2 is split into 2 part m1 and m2 by internal explosion which generate kinetic energy K. If they move in the same line after explosion, show the speed of one part relative to the other part is Square root of ( 2K(m1+m2)/m1m2) Homework Equations The...

Basically I have been given this question: A battery of unknown EMF and internal resistance is connected in series with an ammeter and a resistance box. The current was 2.0A when R= 4.0 Ohms and 1.5A when R= 6.0 Ohms. Calculate the EMF and internal resistance. I feel you may have to...

Homework Statement Two resistors R1= 132 ohms and R2= 56 ohms are connected to a 6.00 V battery with an internal resistance of 5.00 ohms. Find the voltage across R2 and the current through R1 a) if the resistors are connected in series, and b) if they are connected in parallel. Homework...

What sort of circuit would I have to set up to figure out the internal resistance of a dry cell? Also, what would i need to be measuring and doing etc, to find this internal resistance? Thanks, Jack.

Does anyone have a quick way of estimating the amount of internal pressure a sealed tube would be able to handle without failing?

\Delta U = Q - W = Q - PV (where PV is the work done BY the system). \Delta H = \Delta U + PV (where PV is work done BY the system). 1) Above I defined PV in both equations as work done BY the system. I think this must be correct to show that when P is constant we can have \Delta H = Q...

If we apply 300 kJ of heat to 2500 moles of air at constant pressure, what is the change in internal energy? So far i think I use the equation: (f/x)nkT, but I don't know how to calculate the degrees of freedom and whether I do or not, and whether or not to calculate the number of moles by...

Hi, This is not exactly homework, but I'm not sure it belongs in any other section either. I've been reading through Applied Thermodynamics for Engineering Technologists by Eastop & McConkey. In general it's pretty good I think. However, in the first few chapters, it explained that Q+W =...

Q: 20 J of heat energy is added to an ideal gas while -40J of work is done BY the same gas. The total change in internal thermal energy of the system is what? Equations I used: \DeltaEth = Heat + Work \DeltaEth = Heat - Ws This was a problem on a recent physics test I took and I said...

“mirage” is refraction phenomenon or total internal reflection phenomenon? “mirage” is refraction phenomenon or total internal reflection phenomenon?

Homework Statement A solar cell generates a potential difference of 0.10 V when a 400 ohm resistor is connected across it, and a potential difference of 0.15 V when a 900 ohm resistor is substituted. What is the internal resistance of the solar cell? Homework Equations E - ir - iR = 0...

Homework Statement A point source of light is at depth h below the surface of a large and deep lake. Show that the fraction, f, of the light energy that escapes directly form the water surface is independent of h and is given by f=0.5(1-\sqrt{1-1/n^2}) where n is the index of...

This inquiry is in relation to internal combustion engines. I am trying to figure out how to maximize the mass of air going into my engine. Because the more air that can get into the cylinder, the more power the motor can make. Now I've been researching Bernoulli's Principle and as I understand...

Homework Statement (a) In the figure shown, show that the rate at which energy is dissipated in R as thermal energy is a maximum when R = r. (b) Show that this maximum power is P = EMF2/4r. http://www.practicalphysics.org/imageLibrary/jpeg400/208.jpg The only difference between this...

Homework Statement two identical cells of emf E and internal resistance r are connected in series. a 7 ohm resistor is connected across the combination and draws a current of 0.333A. the two cells are now connected in parallel; the 7 ohm resistor now draws a current of 0.375A from the...

What is the difference between them. Even in total internal reflection not everything is reflected. I don't get it what is the big deal?