Balance Definition and 491 Threads

when a can of coke placed in a sensitive balance is opened what happens to the reading? the answer of this question is given first increases and decreases. can anyone explain this?

Homework Statement You are to design, build and test a method to accurately measure the mass of an object. You cannot directly weigh the object but must use experimental data to determine your result. You cannot build any type of spring balance or beam balance. You are to determine your method...

Homework Statement Hello all, this is my first post and I'm hoping someone with more of a physics background can help me... I'm trying to determine the energy absorbed by some opaque material at the bottom of a hole of uniform radius filled with fresh water. The hole is located within a...

I bought some fruits from the market yesterday and after returning home, I found that some fruits were not weighed properly. In my country (India), they use traditional beam balances. I ordered for 0.5 kg berries and found that they were only 360g on an electronic balance. Does anyone here know...

Homework Statement A piston-cylinder assembly contains water, initially saturated liquid at 150 degrees C. The water is heated at constant temperature. a) if the rate of heat transfer to the water is 2.28 kW, determine the rate at which work is done by the water on the piston, in kW.Homework...

I was trying to figure out the following - assume you have an old fashioned balance scale, with two pans hanging from a lever with a fulcrum in the middle of the lever. On one side you have a weight of X, and on the other side you have a weight Y. If Y is big enough, that side of the scale...

A spring balance cannot be used to measure the weight of anything under the conditions of a space shuttle. Is there any way you might use a spring balance to compare the 'heaviness' of twin babies born on the shuttle? Discuss. I don't know how you'd use a spring balance in the shuttle.. Any...

https://www.physicsforums.com/attachments/33615 I have problem with these two questions, can you give me a hint and help to understand it, I do understand problem 7-3 but i have problem with applying the equastion, I don't understand to 7-2 but i knw we have to have an addition term for the...

I am doing a problem about steam flowing through a nozzle. Here are the initial and final conditions.. P1=30 bar = 3000kPa T1=320 C v= 100 m/s (v= velocity!) P2=10 bar = 1000kPa T2= 200 C Mass flow rate = 2 kg/s (Steady flow process) To me it seems like a cut and dry energy balance problem...

Homework Statement A furnace is fired with 1000 feet cubed per hour at 60 degrees F and 1 atm of a natural gas containing the following volumetric analysis: CH4: 80%, C2H6: 16%, O2: 2%, CO2: 1%, and N2: 1%. The exit flue gas temperature is 800 degrees F and the pressure is 760 mm Hg absolute...

I am going over some thermodynamics right now and I am looking at the energy balance equation which is dE/dt = mdot*j(in) - mdot*j(out) + Qdot + Wdot(external) I understand this means that the change in energy with respect to time equals the sum of the mass energy that goes into a system, minus...

I'm looking at a surface at an angle. Light reflected to me is polarised (Fresnel), does this mean light emitted to me from the surface is also polarised? I've been told that ocean emission is polarised (when looking at an angle) because of Kirchoff's law of radiative balance (emissivity =...

If an ordinary balance with two equal weights is displaced slightly from its equilibrium position then it regains its original position. Why? There is no unbalanced torque at any position. So why should it regain its position? I am totally confused on this one. Can anyone help...

Homework Statement Describe how you would prepare exactly 250 mL of .180 M K2S2O8 solution for use. Assume that you have a supply of solid K2S2O8, deionized water, a balance, and a volumetric flask. Also, how many grams of K2S2O8 would you need? Homework Equations The Attempt at a...

http://www.ted.com/talks/nigel_marsh_how_to_make_work_life_balance_work.html?utm_source=newsletter_weekly_2011-02-08&utm_campaign=newsletter_weekly&utm_medium=email" Nigel has a dry sense of humor, even though a few lines I have heard in other contexts before, IMHO, worth watching...

Homework Statement 10 g Fe and x ml H2SO4 forms y gFeSO4*7H2O Write a balanced chemical equation for the reaction, and determine the coeffisients y and x. The H2SO4 is 1 M. Homework Equations n=V*c n=m/Fm The Attempt at a Solution First thing I was trying to set up the chemical...

I was just about to apply for my pell grant and it wanted me to tell them how much I have in my bank account. How much will that affect how much money I get from the grant? Does anyone know? If I have a lot, like 10 thousand, will that make me get a lot less, or none? Or if I have under 2...

Haven't taken a course in distillation in a long time and now myself and some others are working on getting a fuel ethanol still going and wanted to do the calculations before we moved forward. We have a beer that is 12% alcohol and reaching a purity of 90% EtOH in the distillate. The mass...

like this: 1)H2SO4 + Al(OH)3 --> Al2(SO4)3 + H2O 2)Pb2+ + Cl- --> PbCl2 and word equation like this ethane(C2H6) + Oxygen --> Carbon dioxide + Water vapour Thq.

There are two main issues I'm interested in for this thread, and how far should regulations have to go to control these issues? 1. The conflict where an individual is in a position to make decisions that benefit the individual at the risk or detriment of the company or other employees...

Homework Statement Toluene is recovered from a mixture of toluene and nitrogen (containing 52 mol% toluene) by cooling the mixture at constant pressure of 1.2 bar to condense out some of the toluene. If the flow rate of the mixture into the condenser is 179 kmol h-1, determine the flowrate of...

Homework Statement Two pans of a balance are 50cm apart. If the fulcrum is displaced by 1cm what percentage is the true weight marked up? Homework Equations T=rFsinθ F=mg The Attempt at a Solution I solved for torque of the fulcrum in a hypothetical situation where a mass of 1g is...

Homework Statement Background: This is a problem I made up as part of an extra credit assignment for my first dynamics (engineering) class. I know the system will of course roll over, and he will end up looking like a fool, but that is besides the point. Keep in mind also that I can modify...

I am really struggling to get to grips with this question, ( struggling with material balance overall!) I can do dimple material balance however for things with a recycle stream or purge stream, really confuses me. I have the solution which I will post up, but I still don't get 'why' it...

By definition, the difference between Mass and Weight is easy to comprehend. However, I am really confused, confused to the level I feel like ripping all the hair out of my head, with spring balances: After researching a lot, I think that as I step on a spring balance the spring will extend...

Homework Statement Hi, I need your help in my homework. My Instructor asked that question? Why there is not a work term in entropy balance equation? Homework Equations The Attempt at a Solution I have researched about it and I found that, entropy has not an exact physical...

I have been working on what I thought was an easy problem. This was a one hour quiz in which the whole class failed, the instructor decided to give it as a homework assignment instead. ------problem start--------- Considerable interest exists in the conversion of coal into liquid products...

Homework Statement 1) A spill of 5kg of a soluble pesticide takes place into a well-mixed pond. The pesticide is subject to volatilization that can be characterized by the first order flux J=VvC, where Vv = volatilization mass-transfer coefficient of 0.01m/d. Other parameters for the pond...

Hello I am trying to design a force balance lever system. Basically the initial state will in a force balance equilibrium. That is, there will be a mass m placed onto of the capacitor plate to keep the lever balanced. I will then ramp the voltage of the capacitor up, causing a force of...

Hi guys, I wanted to know these things with their respective examples : 1. What is an atom ? 2. What is a particle ? 3. Why do we use/calculate the atoms of an element to balance an equation ? Please answer to these questions guys, because I only have 2 days for my exams and to know them.

Homework Statement Use a shell balance method to derive the equation governing the two dimensional temperature distribution,u, in a circular disk in polar coordinate system(r,theta). allow for the possibility of differing thermal conductivities in the r and theta directions. Homework...

It it normal to like physics research better than solving problems for coursework? Is physics coursework in the U.S. is too problem-solving oriented? Thanks

Assume that you have two protons accelerated in opposite directions within a cyclotron. As they approach the speed of light their masses increase. At what proportion of the speed of light will their gravitational attraction (due to their increased mass) equal their electrostatic repulsion ?

Homework Statement A body weighs 6 gms when placed in one pan and 24 gms when placed on the other pan of a false balance. If the beam is horizontal when both the pans are empty, the true weight of the body is : Homework Equations The Attempt at a Solution I don't know which...

In my statistical mechanics class, my prof derived DBP in the following way: Consider a system with many quantum states |a>, |b>..., keep scattering with each other and in equilibrium the master equation give us : \frac{{d{P_k}}}{{dt}} = \sum\limits_{l \ne k} {{T_{kl}}} {P_l} - {T_{lk}}{P_k}...

Homework Statement A mass, m = 175 gram is placed on a hanger which has a mass of 50 g, giving a total mass of 225 g. The hanger is then hung at an angle of 120° over a pulley attached to the force table by using a string of negligible mass. The pulley over which the string rests has very low...

Ag(subscript of 2)S + HNO(subscript of 2) -> Ag(subs.2)SO(subs.4) + NO(subs.2) +H(subs2)O TNX! PO!

Homework Statement This was a concept question my lecturer gave us, and although he tried to explain it thoroughly, I still didn't get it. So I was hoping someone could help me out. There are 2 parts to this question Firstly a spring balance is attached hanging from a celling using a...

[b]1. First off i am not a student per say, this is related to my hobby I am repairing an old clock and need to replace the balance spring which is completely missing. I have located ONE source that may carry suitable springs but I cannot figure out which spring to order. The spring...

Homework Statement Homework Equations ordinary mass balance The Attempt at a Solution So far I have gotten: d[rhob*V]/dt = Min - ?

Homework Statement what is the measurement Homework Equations The Attempt at a Solution Is there something wrong with the picture or is it possible to have beam balance with two same scales (the upper and middle ones). If possible then the reading = 90 + 30 + 8 = 128 g ...

consider a weight balance with two unequal masses on the two arms.It comes to rest after tilting a few degrees. If one of the masses really experienced a greater force, then there is no reason why the balance shouldn't tilt 90 degrees

If a organism has a dna mutation, would this not imply that some trait is lost. If there is a mutation then somewhere in the dna there is a difference which would cause something to be missing. Is this right? If this is the case then how come complicated speices still have all there original...

Wondering if you have time for a (hopefully) quick math question: To put it simply, the equation is as follows: (xA + zB) / (x + z) = y Where all values except x are pre-determined, and x needs to be changed so the left equation equals y. y represents the center of gravity for a...

Im having difficulty with question b in this problem: [PLAIN]http://img705.imageshack.us/img705/9484/therm.jpg Heres my attempt: m(v1^2)*1/2)+h1)=m(v2^2)*1/2)+h2) + Qout (v1^2)*1/2)+h1)=(v2^2)*1/2)+h2) + Qout where v1 = 200ms^1 and v2 = 40ms^-1 and h1 = 3104.9kj/kg And my answer is 22,000kj/kg...

Homework Statement A rock is attached to the left end of a uniform meter stick that has the same mass as the rock. How far from the left end of the stick should the triangular object be placed so that the combination of meter stick and rock is in balance? a. 0.25 m. b. between 0.25 m...

1. If you walk along the top of a fence, why does holding your arms out help you to keep your balance? 2. Charge is also said to be conserved. What does it mean? Explain. 3. When a car drives off a cliff, why does it rotate forward as it falls? 4. Why does a book sitting on...

Hey, I was wondering in what way the detailed balance condition (DBC) has to do with thermodynamic equilibrium. The DBC is defined as W(i\to j)P(i) = W(j\to i)P(j) with W the rates (probabilities per unit time) to jump from state i to j. P(i) is the equilibrium prob. density to have...

Homework Statement While using a current balance to experimentally determine mu0 (4PI*10-7), two mu0 values were found (current was reversed to find one of these values) and averaged together in order to partially compensate for the effect of the Earth's field. Why does the flipping...

I find it tough to balance my research and my family and wonder how others succeed in this regard. Every serious researcher will agree, I hope, that research demands undivided attention for high quality work. How can then a researcher take care of her/his family adequately? Should she/he...