Balance Definition and 491 Threads

http://www.powerbalance.com/ Has anyone researched the power balance bracelet? I bought one for $30 and I'm going to test it on some high schoolers. I think everyone here would be convinced that this is complete quackery, however, I think there is still a valuable lesson about peer review...

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The scale of a spring balance reading from zero to 180 N is 7.00 cm long. A fish suspended from the balance is observed to oscillate vertically at 2.50 Hz. What is the mass of the fish? Neglect the mass of the spring. ________ kg Attempt k =(180-0)/(7-0) = 25.714 N/m frequency =...

Homework Statement Ok, please use my example of giving me a step by step guide on how to balance an equation: Homework Equations K + Br2 --> KBr The Attempt at a Solution I know that I should write down the equation, draw a line underneath the arrow to separate the balancing...

Hey guys i was hoping for some help with the mass balance of the equations for the production of styrene from ethylbenzene. I have attached my problem sheet and my answer sheet, q 7 is what i am stuck on please help me i am confused

Homework Statement A steel girder with a mass of 1000kg and a length of 10m rests on a concrete slab, with 4m overhanging the edge. How far can a 100kg man walk on the girder? The Attempt at a Solution I supposed that the right end of the slab is the fulcrum (rotating point), and...

I would appretiate help with the following 2 questions, I think I've got must of the first one right (Or went off t a tangent) but I don't now where to start on the second question 1a) Calculate the flue gas composition if 100 kmol h-1 of a gas whose composition is given below are burnt with...

For example, if we have 2-butanol, a compound with a secondary \alpha carbon and I reacted this with HCl and NH4Br I would get 2-bromobutane (via nucleophillic substitution), but how would I determine whether this goes via SN1 or SN2 to achieve this? Now, if this was 1-bromobutane, I know...

Homework Statement Hi all. I've got a vertical rod on a surface with a fixed and frictionless pivot at bottom end. The rod of length L is released and begins to fall. The forces acting on the CM of the rod should be: - weight force: mg - centripetal (radial) force...

Hello, I am just thinking: why it is hard to balanca a (2-wheel) bicycle when it is not moving, while it is easy balanced when it is moving? I hope that I am asking in the right forum. Thanks in advance

Homework Statement Question: A mixture of 40/60 mole% pentane/heptane is to be separated to give a top product of 95 mole% pentane and a bottom product of 5 mole% pentane. The column will operate at 1 bar witha reflux ratio of 0.5 kmol/kmol. It will have a total condenser and a partial...

Homework Statement A man of mass mm = 90 kg decides to paint his house. To do this, he builds a platform using a uniform beam with a mass of mb = 91 kg and a length of L = 7 meters. The beam is supported by two sawhorses, ---------------------- A B (distance from A to left...

Hi I'm doing a practice paper for a past mathematical modelling exam. I've attached the problem What I'm having trouble with is simplifying the equations and variables into a differential equation that is solvable with Euler's Method. What I have currently is the sqrt(h1-h2) in the...

I messed up on the title of the thread.. I had a few questions but ended up solving them on my own. The only question I have is how to solve this ODE. Thanks. Homework Statement Solve the ODE (dx/dt)= f(t) - .1x Where f(t) = 2+sin(t)2. The attempt at a solution I faintly remember doing...

Homework Statement BCl3+H2O2>>H3 BO3+HCl Homework Equations need to balanc it The Attempt at a Solution

Homework Statement A point charge q = -0.5nC is fixed at the origin. Where must a proton be placed in order for the electrical force acting on it to be exactly opposite its weight? Homework Equations F= k(q1)(q2) ------------ r^2 The Attempt at a Solution Trying to...

Hello, I am trying to make something that spins out of balance. currently my current weighs are half circle in shape. I know that if I change the profile of the weights to a pie shape (less than 180deg semi circle) the center of mass moves away from the axis of rotation, but at the same time...

Homework Statement In this era of high energy prices, there is a focus on renewable sources of energy such as wind energy. Consider a large windmill 30m in diameter. On a windy day, suppose that the windmill entrains a stream of air 25 m in diameter at a speed of 14 m/s. Downstream of the...

Fox News clearly picks a side when it comes to debates. How do you consider this fair and balance?How can they claim they are they only non-corrupt network? What did Obama gave CNN? What sides of any issue has a CNN news caster picked?

Q-1 : A bodu weighs 8 gm when placed in one pan and 18 when placed on a other pan of a false balance . If the beam is horizontal when both the pans are empty , the true weight of the body is Q-2 : when one swims across a river max. energy is spent in second 1/3 of the distance why ?

1. A Wheat stone bridge resembling setup is given with two parallel branches , the 1st containing an Inductor of Inductance L1 and resistance R1 in series with a resistor R2. The second branch consists of inductor with inductance L2 and resistance R3 in series with a resistor R4. The branches...

I am curious. Maybe I don't understand something, but many articles I come across perform an energy balance on a solid and on a liquid. **I assume evaporation acts on the remaining liquid and not directly on the substrate. Correct?** They always include heat loss due to evaporation as...

A uniform plank us supported by a hinge at one end. What is the magnitude (expressed as a multiple of the plank's weight Fg) of the upward force you have to exert on the other end to keep the plank at rest and level?

Homework Statement A beaker with water is in equilibrium with a certain weight in a balance. Then we tie a cord to a stone, and soak the stone in water, without touching the bottom. What will the balance read and why? http://dl.getdropbox.com/u/698994/ilustra%20forums/experiencia%20empuxo.png...

Do plants absorb as much carbon-dioxide as they release? Is there a CO2 balance, deficit, or surplus in the plant world?

Hi guys, I'm working on a prototype for a lamp and have quickly overreached my meagre school boy mechanics skills, almost at the first hurdle, in fact. Embarrassing, I know, but hopefully some kind soul here will be able to point me in the right direction. A picture is worth a thousand words...

does anyone no of a math formula to balance uneven weights? say if i had a 100g (3.5oz) weight on a bar 100mm (3.9in) from a center point and another weight of 150g (5.5oz) how far will it need to be from the center to level the bar. could it be as simple as double the weight double the...

Homework Statement I'm doing an assignment involving a current balance, and the one thing I don't understand is the currents. I have two separate currents, one labeled "Current in Solenoid" and another labeled "Current in Loop". Now, I know the current in the loop is the part that causes...

Homework Statement Balance the equation (Note: the coefficients provided may be wrong): 3 Co(s) + 8 H+(aq) + 8 NO3-(aq) → 3 Co2+(aq) + 6 NO3-(aq) + 2 NO(g) + 4 H2O(l) The Attempt at a Solution I started out by doing a half reaction Co → Co 2+ +2e- This...

Homework Statement There are three different reactions we did in class. B-: 6C14 --> 7N14 + e- B+: 6C11 --> 5B11 + e+ Nuclear rxn: alpha particle + 7N14 --> 8O17 + e+ Homework Equations Q tot = (mass inital - mass final) * 931.5 MeV Charge balance The Attempt at a Solution In...

Here is my current situation, as a high school drop out, I can continue my education at a so called Adult Education Center. This means I can choose my schedule that best fits my needs. Here is the thing, should I do only 2 classes a day and try my best to get close to 100% in my classes, or...

A mass is winded via string aroung a flywheel and allowed to fall a specific height before detachement. The flywheel is connected to a small DC motor via gears and starts generating electricity once the mass is allowed to fall.. Now without the DC motor ( generator) the equation of energy...

Recently, I've gotten into a kind of crisis mode. I am a third year undergraduate majoring in physics. Last semester, I've overloaded myself with graduate courses and dragged through it with good marks at the end. My social life was pretty much non-existent. I slowly realized that I cannot...

Hello, what is the assumed balance between neg, pos and nuetral charge in the whole universe? Does it balance out to nuetral? Ta Chris

Homework Statement Ethane reacts with chlorine to make ethyl chloride and hydrogen chloride, and ethylene reacts with hydrogen chloride to form ethyl chloride. C2h6+ Cl2 > C2H5Cl + HCL C2H4 + HCl > C2H5Cl I post an image of flow chart and rest of description Based on my reading...

Homework Statement A fan loses an 11 gram piece 460mm from the shaft center. It rotates at 1000 RPM and cannot operate if the shaft is out of balance by more than 8%. Prove whether or not the fan can still operate Homework Equations Fc = mwr2 The Attempt at a Solution I have...

Homework Statement A fan loses an 11 gram piece 460mm from the shaft center. It rotates at 1000 RPM and cannot operate if the shaft is out of balance by more than 8%. Prove whether or not the fan can still operate. Homework Equations Fc = mwr2 The Attempt at a Solution I have...

Well I have the answer already, just don't understand it. A rectangular coil of wire is hung from one arm of a balance, as my beautiful diagram will show. With the magnetic turned off, a Mass M is added to the pan on the other arm to balance the weight of the coil. When a constant magnetic...

What's the purpose of "thrust balance" in Turbo Fan Engine? I'd like to know about the purpose of the Thrust balance system in commercial Turbo Fan Engine. Can you tell me the major role of thrust balance system? Also, the relations between thrust balance system and compressor / main bearing...

Help! I've spent 2 days now trying to do this now and it driving me mad. http://www.emvino.com/pivot.jpg Given the following diagram, what distance from the pivot (x) is required to balance the beam? any help would be highly appreciated. Thanks

Ca_3(PO_4)_2 + H_3PO_4 -> Ca(H_2PO_4)_2 i got the same problem with this one MgO + H_3PO_4 -> Mg_3(PO_4)_2 + H_2O each time i balance one element i get the other which i balance before to be dis balanced what is the general way of solving such things ??

The senses are, in a nutshell, methods by which we gather information about the outside world. I've never understood why balance is not considered a sixth sense. It is a way that we gather information about the outside world that is unique from the other senses. It tells us which way is down...

A hydraulic balance used to detect small changes in mass is shown in Fig. 9.31. If a mass m of 0.40 g is placed on the balance platform, by how much will the height of the water in the smaller, 1.0 cm diameter cylinder have changed when the balance comes to equilibrium? please give a detailed...

Homework Statement 1. If the Sun’s power is reduced by 10%, what would the temperature of the Earth be? Assume an albedo of 0.3 and do not consider greenhouse effects. Homework Equations There is an equation here in the book but it makes no sense to me The Attempt at a Solution...

This is just a problem from my midterm, and I was wondering if I did it correctly Homework Statement Weight of block B is 15kN, weight of block A is 25kN. Find force P that has to be applied to keep the system in equilibrium in tension in the cable Homework Equations \sumFx=0...

Three boys are trying to balance on a seesaw, which consists of a fulcrum rock, acting as a pivot at the center, and a very light board L = 3.52 m long, see figure below. Two boys are already on either end. One has a mass of m1 = 53.0 kg, and the other a mass of m2 = 32.8 kg. How far from the...

My main question in order to solve this problem is...should kinetic energy be neglected? Ok, so here's the problem question: Sea water with a density of rho = 1025 (kg/m^3) flows through a pump of 0.21 (m^3/s). The pump inlet is 0.25 (m) in diameter. At the inlet the pressure is -0.15 (m of...

Hello everybody.. I have aquestion and hope to get help..please bear with me and try to finish reading my question.. Thank u very much for your time. My question is I have a pilot plant filter.. and i need to add some chemicals to the raw water before entering the filter..say for...

You are given 12 coins that are identical except that they are numbered and you are told that one coin is odd-weighted, being either slightly lighter or slightly heavier than anyone of the remaining eleven. You are given a worktable and a balance beam scale. You may use the scale three times...

I have constructed a wind tunnel with approximately 15 x 15 in. cross-sectional area test section. Where can i get some ideas/plans to build a simple force balance that can measure lift and drag forces simultaneously? Currently I'm using a single-axis button load-cell setup to measure...