Mass

Question: mass??????? Ricardo, mass 82 kg and Carmelita, who is lighter, are enjoying Lake Merced at dusk in a 30 kg canoe. When the canoe is at rest in the placid water, they exchange seats, which are 3.0 m apart and symmetrically located with respect to the center of the canoe. Ricardo notices that the canoe moved 48.5 cm relative to a submerged log during the exchange and calculates Carmelita's mass, which she has not told him. What is it?

Answer: 82*3-m*3=82*(3-.485)-30*.485-m*(3+.485) solve for m m=(82*(.485)+30*.485)/.485 112 or, since it wasn't specified which direction the canoe moved m=(82*(.485)-30*.485)/.485 52 _____________-

Question: How much mass does an object have to obtain for it to have a gravitational force? As everyone knows the more mass an object has the more its gravitational force. But i was wondering what the minimum amount of mass an object has to have for it to have a gravitational force. For example the average human weighs about 150lbs. Weight is like mass. So if a human can have this much weight, and not a gravitational pull, then that means that there must be a certain mass, and when this mass is obtained, that an object has to reach to have a gravitational force.

Answer: Any amount of mass, no matter how small. The gravitational pull of a 100-kilogram (220.46 pounds) man to another of the same weight standing next to him is 0.000010678848 Newtons, which converts to 0.00003841 ounces. Far too little for a human to feel, but present and measurable. The same units are used for mass and for weight and cause no end to confusion. Mass is not weight. .

Question: Mass Murderer psychology including What makes mass murderers target some, but leave others? On the PBS Newshour show (Thursday, 16/04) they done a report on Mass Murders in America. Also there has been a massive increase in the recent month. (Just interested, what goes through their head) Secondly, why do killers decide to kill some people, when the main aim is mass murder?

Answer: I think that is a very interesting question. The reason we don't understand what goes thru their heads is because the majority of us can't fathom the idea of death. It is not a game/sport to us. Just like a rapist. How do they pick their targets? Sociopaths aren't like the rest of us. We can read all the books we want and watch all the movies and still not understand why they are the way they are. Hence the term "crazy". You can become an FBI profiler and know what to look for but never fully understand the "why". It's a dangerous game. The best we can do is go on with our daily lives and hope we don't become the prey. Save our sanity!

Question: How is the internal mass structure associated with Kinetic energy when the mass is started moving? Is mass increased or decreased. If mass increases it must gain it from outside influence in other words, mass gain is not intrinsic. Or if there is mass loss, it is intrinsic.Than what happens to kinetic energy and potential energy? 2nd law of thermodynamics. say you get nothing for nothing.in oder to get somthing to move you have to pay some Price? the price of gasoline is indeed high.

Answer: How would you lose mass? By Newton, the mass must not change. By Einstein, the mass slightly inscreases.

Question: What is the mass of an airtight container if the chemical in it has been burned? You have a chemical sealed in a glass container filled with air. The glass container has a mass of 200.0 grams and the chemical has a mass of 600 grams. The total mass of the set-up is 800 grams. The chemical is ignited by means of a magnifying glass focusing sunlight onto the reactant. After the chemical is completely burned, what is the total mass of the set-up?

Answer: 800 grams due to the law of conservation of matter

Question: What's the difference between invariant mass and relativistic mass? If mass increases as a particle approaches the speed of light, the mass of even an electron will tend towards infinity. There would come a point where the electron's increase in mass would create non-negligable gravitational effects. By this logic, a particle moving near the speed of light could become a black hole. Looking at it from the electron's perspective, the whole universe is moving past it at about the speed of light and it too would have such a mass increase that even the smallest of objects would become black holes. Obviously, this doesn't happen. There must be some crucial distinction between invariant mass and relativistic mass the prevents this ludicrous conclusion from actually happening. What is the distinction?

Answer: What you are saying is that relativistic mass Mr=LM where L is a Lorentz factor L= 1/SQRT(1-v^2/c^2). Indeed L becomes infinite as v of the mass M approaches c or the speed of light. The mass M becomes Mr and it is bigger then any black hole! Well it is time to introduce a statement like at the transition point the laws of no longer apply. Yes I know it a bad excuse. However the mass of a photon at rest is zero like in 0. How convenient. If it was not a so then a single photon could suck in …, o my, the whole Universe or just us. I agree we need a model for an intermediate mass. I would let the champions of the string theory to shine some light on that question. I’m so happy we are still here. :)

Question: What mass of silver nitrate must be used to completely precipitate the chloride ion from the sample? please help me out asap!!! Suppose a 1.441-g sample is known to contain 12.5 % chloride ion by mass. What mass of silver nitrate must be used to completely precipitate the chloride ion from the sample? What mass of silver chloride will be obtained?

Answer: Hi angela....im stuck on the same problem...hahahaha Silver nitrate is highly soluble salt and when it is dissolved it forms silver and nitrate ions: AgNO3(aq) -----> Ag^+(aq) + NO3^-(aq) Silver ions react with chloride ions present in the solution and forms insoluble silver chloride: Ag^+(aq) + Cl^-(aq) -------> AgCl(s) This is the net ionic equation of the reaction. Mass of the sample:1.441 g Mass of Cl- ions in the sample: 1.441 x (12.5/100) = 0.180125 g Molar mass of Cl = 35.5 g /mol Mole of Cl- ions = 0.180125 g / 35.5 g/mol = 0.0050739mol According to net ionic equation; 1 mol Ag^+ ion is necessary to precipitate 1 mol Cl^- ion, therefore for 0.0050739 mol Cl^- ion we will need 0.0050739 mol Ag^+ ion. According to dissolving equation; AgNO3(aq) -----> Ag^+(aq) + NO3^-(aq) 0.0050739 mol Ag^+ ion will be produced by 0.0050739 mol AgNO3 Molar mass of AgNO3 = 170 g /mol Mass of AgNO3 required : 0.0050739 mol x 170 g/mol = .863 g

Question: How to calculate atomic mass of hydrogen? I know the equation to find the atomic mass of an element is (Mass Iso1 x Percent Abundance Iso1) + (Mass Iso2 x Percent Abundance Iso2) = Atomic Mass and I know that hydrogen has two isotopes (deuterium and tritium), but I don't know what to do from there. Please show me your calculations so I know how you got your answer. Thanks for any help! How do you find the numbers and percentages?

Answer: You need to know mass of 1H, mass of 2H (aka D), and percentages. Otherwise you can't work it out. How could you? Then just shove the numbers in to the formula you've written down.

Question: What is the difference between inertial mass and gravitational mass? What is the difference between inertial mass and gravitational mass? If an object's inertial mass is equal to its gravitational mass, why do we have ti differentiate between them?

Answer: Because we want explicit distinction. There are three types of mass: inertial, the one the second law of newton, F= ma active gravitational, that mass M in g = GM/r², and passive gravitational, that mass m in F = mg. These three masses are belived to be equal but not EQUIVALENT. The physicists want t know why the three masses are ALWAYS equal, and if there may be any exceptions. This would be called super-unification.

Question: How is it possible to find the mass of atomic particles? I mostly am looking for a clarification of how it is possible to obtain a mass value for an electron or proton as understood by quantum mechanics. Since both protons and electrons are subject to the uncertainty principle and their interactive force is the "weak atomic" force. Which i believe is based on charge and independent of mass. How would it be possible to measure a mass value? Or are atomic mass values just an estimate based on the the mass of an element and a guess as to how many atoms make up that mass?

Answer: The mass of an electron can be determined using two experiments, in conjunction. The first is rather simple. We know that a charged particle in a magnetic field will feel a force perpendicular to its velocity. From this you can find the charge-to-mass ratio of an electron. The experiment goes as follows. You heat a metal filament (usually tungsten) by passing a current through it, basically like a light bulb. Once the filament gets hot enough, it starts to boil of electrons. You can accelerate those electrons using an electric field, to give them some velocity. You then let the fast electrons enter a region of magnetic field, which will cause the electrons to travel in a circular path due to the perpendicular force. As it turns out, by measuring the radius of that circular path (which would be inches), you can find the charge-to-mass ratio of an electron. The way the radius is measured is by doing this in a gigantic vacuum cell with a little bit of gas in there. The electrons are moving fast enough that when they collide with the gas, they cause the gas to light up. By passing a huge number of electrons through the apparatus and having a low enough density of gas that only a fraction of the electrons actually collide with a gas molecule during the circular path, you can actually see the circular path with your eyes. This may sound like a far out experiment, but they were really doing this, successfully, a hundred years ago. And, in fact, I have done this experiment too. So that gives you the charge to mass ratio. How do you find the mass? Well, you just have to find the charge of an electron. This was done in a famous experiment, called the Millikan Oil Drop Experiment. Basically, Robert Millikan realized that when you spray oil out of a perfume sprayer, it will often create charged oil droplets. Millikan took a sprayer, and made a fine mist of charged oil drops and placed those drops between two parallel plates with a voltage difference between them. He made it so that the electric force pushed the oil droplets up and exactly balanced the force of gravity down. He could measure the size of the droplet with a microscope and he knew the density of oil, so he knew the mass of the droplet. He also knew the gravitational acceleration and, from that, he could find the gravitational force on each droplet. Since the electric force equals the gravitational force, when they are balanced, he then knew the electric force, which is proportional to the charge in each droplet. He did this for hundreds of droplets and realized, after looking at many droplets, that the charge on each droplet always came in discrete steps. He concluded that that was because the charge was coming from discrete electrons. Since he had measured that charge, he could give a value for the charge of an electron. Given the charge and the charge to mass ratio, it was trivial to find the mass. And there you go, that is how we first measured the mass of electrons. Since then, there have been many other methods that were more accurate and precise. Protons can be measured in similar ways, though it is a bit more difficult (but not impossible) to make a source of protons.

Question: How do you calculate mass or what is the formula for mass? Im trying to get the mass for an An-124 Cargo plane. If you know the mass that would be great otherwise can you tell me the formula in order to get mass.

Answer: Mass is constant. Weight changes. For instance, your weight on earth is different than your weight on the moon. Or your weight on Jupiter. Therefore, I think you are actually asking for the weight of the An-124, which will vary depending on fuel and what sort of cargo it carries. You will find the weights and other specifications here: http://en.wikipedia.org/wiki/Antonov_An-124#Specifications Regards, Mysstere

Question: What is the difference between the molar mass and the empircal formula mass of a compound? What is the difference between the molar mass and the empircal formula mass of a compound? When are these masses the same? And When are they different? When different how is the molar mass related to the empirical formula mass?

Answer: Molar mass refers to the mass of one mole of a pure substance. For instance, 6.022 x 10^23 molecules of H2O has a molar mass of about 18.015 g/mole. The empirical formula mass is the mass of one mole of the formula of a substance which is reduced to lowest terms. For instance, the empirical formula of a simple carbohydrate is CH2O, while glucose, a simple sugar has a molecular formula of C6H12O6, or C6(H2O)6. If the masses are the same then the empirical formula is the same as the molecular formula. The two quantities are different when the actual molecular formula has a greater mass than the empirical formula mass. e.g., empirical formula CH3 has a mass of 15 g/mole, while the simplest molecule with this empirical formula is C2H6 with a molar mass of 30 g/mole. If they are different then the molar mass of the actual molecule will be some simple multiple of the empirical formula mass.

Question: How to find mass of element when calculating average atomic mass? The problem is to calculate the average atomic mass: Rb, which consists of rubidium-85 (72.2%) and rubidium-87 (27.8%) So I got this part down: (.722) ( mass #1) + (.278) ( mass #2) = ? I don't know what to put in for the masses. I think I'm making the problem harder than it is. But are you supposed to plug in 85 for mass #1 and 87 for mass #2?

Answer: Look here: http://en.wikipedia.org/wiki/Rubidium Rb-85: 84.911789738 Rb-87: 86.909180527 Approach is correct, just insert these.

Question: What is the difference between mass number and atomic mass? If you just read the definition from the book "Mass number" is equal to the sum of protons and neutrons in an atom's nucleus while "Atomic Mass" is equal to the mass number. Doesn't that mean that we're using two words to describe the same thing? What's the point of that?

Answer: Atomic mass is the average of the masses of the existing isotopes in an element, but the mass number is the sum of the protons and neutrons in the nucleus of an atom.

Question: What is the mass of a trbuchet to find potential energy? I am doing a project is physics. I need to find out the potential energy of the machine. To find potential energy the equation is mass times gravity(9.8) times height. Is the mass the counterweight or the mass of the flying object in this case.

Answer: As I understand it a trebuchet is a giant catapult, yes? So all the potential energy is contained within the springs, or twisted ropes or rubber bands or whatever holds the arm down. This sounds to complicated without more info. You could get an approx answer by measuring the kinetic energy of the stone when it is released + the kinetic energy of the Trebuchet when it rolls back wards + the energy converted to heat by friction. The total will be the potential energy.

Question: What exactly is mass, and how can something exist yet not possess mass? If something occupies a definite space must it necessarily have mass? Is there a certain force or field that imparts this mass onto an otherwise massless species? Please excuse my ignorance in physics if my question seems spurious. What of the massless Neutrino? Is there even a massless neutrino anyway? Does it not occupy space, however minute?

Answer: This is not at all a spurious or silly question. Indeed it is so basic that it is difficult to answer. The mass of an object is a fundamental property of the object; a numerical measure of its inertia; a fundamental measure of the amount of matter in the object. Definitions of mass often seem circular because it is so basic a quantity that it is hard to define in terms of something else. Another way to express this is to say that mass is a property of an object such that the force needed to accelerate it is proportional to the acceleration and mass is the proportionality constant. Current thinking assigns zero rest mass only to gauge bosons (photons (carriers of electromagnetism) and gluons (carriers of the strong atomic force).)