Weight Definition and 1000 Threads

Dear list, Imagine a table of upper surface area S sitting in an open field, with nothing on it. We know that S is subjected to a downward atmospheric pressure P due to a cylindrical column of air of volume V extending vertically from S to the end of the terrestrial atmosphere. Assume this...

Very often we've identified sets of particles with the weights of a semi-simple Lie algebra - for example, the 8 particles of the baryon octet with the weights of the 8 representation of SU(3) global flavour symmetry (in the old days of the Eightfold Way), or the 3 weak bosons with the weights...

Homework Statement A block of mass (m1) is attached by a massless string to a pulley of mass (m2) with radius R. Starting from rest, what is the block's speed after it has fallen height h? Homework Equations I'll call angular velocity w. I'm thinking conservation of mechanical energy, so...

Homework Statement You are on a roller coaster ride, and enter the bottom of a loop of radius r moving at a velocity v0. You decide to measure your initial velocity v0 by using a simple bathroom scale and a little physics. As you go through the loop, the scale you are sitting on reads 5/2...

Homework Statement The molecular weight of a monoprotic acid HX was to be determined. A sample of 15.126 grams of HX was dissolved in distilled water and the volume were brought to exactly 250mL in a volumetric flask. Several 50mL portions of this solution were titrated against NaOH solution...

Your probably familiar with the solarsail tech when people use light to push space ships with sails. This is light that is pushing matter with mass, I learned in school that in order to have momentum you have to have mass and light has no mass and therefor no momentum. And if you get hit...

Homework Statement Convolution-Summation of a First Order System with Constant Coefficients http://dl.dropbox.com/u/14655573/1.PNG Homework Equations The Attempt at a Solution The solution from the lecture [PLAIN]http://dl.dropbox.com/u/14655573/2.PNG...

Ok, my apologies if this has been dissected on PF before, I did do a few searches and didn't stumble into anything, there doesn't seem to be much info online. Is it woo-woo or legitimate ? ----- Unexplained Weight Gain Transients at the Moment of Death Journal of Scientific Exploration...

Hello all - I'm new to the forum - I hope some kind person can help with a question of calculating scale weight in a scale model of a glider. I want to test the glide ratio of a glider design by making a 1:4 scale model and thowing it from a certain height at a certain speed and measuring...

An object is pulled up by a rope from an elevator traveling upward with an acceleration of 1.4 m/s2. The tension in the rope is 30N. What is the weight of the object. A) 2.6kg B) 3.6kg C)4.6kg D)5.6kg My attempt: FT=30N asystem=1.4m/s2 Weight of object=mg The system is accelerating up, so let...

Homework Statement you are hovering (no acceleration) in a hot air balloon of total weight (balloon+load+hot air) 18,000 N a) what is the weight of displaced air? b) what is the volume of displaced air? Homework Equations if i knew i wouldn't be asking The Attempt at a...

hello a plane would need a thrust to weight ratio of 1 of fly straight up without losing speed but how can a plane in level flight maintain its altitude with <1 TWR since to maintain a level flight you need to have lift = weight so your engine needs to supply enough power to generate...

Homework Statement http://www.edexcel.com/migrationdocuments/GCE%20New%20GCE/GCE-Physics-6PH01.pdf Q22) Homework Equations - The Attempt at a Solution Look at Q22) I could do a and b but had issues with c) for ci) would I be correct in thinking: - The dotted line is...

Homework Statement So you have a cylinder filled with water sitting on a scale. You take a steel ball and drop it in the water. So does the weight on the scale: 1)Immediately change and stay constant including when the ball comes to rest on the bottom 2)Increase immediately when the...

carry weight?? what does the amount of weight a person can carry depend upon ? i think that it depends upon person to person ?? is there any physical constraint like the weight of the man himself or any other factor ?

1. In the experiment(using a Atwood machine), should the mass of the string be added to the total mass moved by the unbalanced force for better accuracy? Explain. I think the answer is no because the weight of the string is very small and when doing the calculations to find acceleration, one...

If I know an object has a mass of 5 kg, and I want to find its weight on earth, I multiply it by 9.81 - right? That equals 49.05 kg. Now, if I want to convert it to Newtons, I multiply it by additional 9.81 So it would equal 481.18 [N]? Is that right?

Homework Statement I am trying to help my lil bro (12 yo) with some physics. I've never been good in physics and now it's been more then 10 years that I've been to elementary school. I've helped him with some stuff but there's this one question that i don't understand and there's very little...

I have 5 different types of balls made out of different materials, all similar but not identical in weight, and all of the the same size. What is the best mechanism to sort these by weight? I can use any mechanical device to sort these balls, such as seesaws, etc. What is the most efficient way?

Homework Statement A muscle builder holds the end of a massless rope. At the end of the rope, a 15 kg ball is hung as shown in the figure. What is the tension in the rope if the angle \theta in the drawing is 4.5^{}o? Homework Equations g = 9.8m/s^{}2 F = mg Trigonometrical functions The...

A friend asked me a question recently... If you were washed up on a desert island - with nothing but yourself, and what the island offers (your standard desert island I guess) - how could you work out a system for mass, distance and time? I've assumed that a system could easily be made -...

Homework Statement so in my physics class, we are learning about the 3 laws of motion and all that jazz bla bla bla, i get all that stuff, just not the stuff where it comes to math. i suck at math! so we had homework, no duh, and well I am stuck, can i please have some help! anyone?? hear...

so in my physics class, we are learning about the 3 laws of motion and all that jazz bla bla bla, i get all that stuff, just not the stuff where it comes to math. i suck at math! so we had homework, no duh, and well I am stuck, can i please have some help! anyone?? hear is the problem: An...

Homework Statement A 1.25-kg mass stretches a vertical spring 0.215 m. If the spring is stretched an additional 0.130 m and released, how long does it take to reach the (new) equilibrium position again? m_object = 1.25 kg A (amplitude) = 0.130 m (since the spring has a new equilibrium at...

Homework Statement http://www.engr.mun.ca/~neil/1010/prob11/set2.pdf" In the first problem in the link above, why is the weight pointing upwards instead of downwards? I thought there will be a different force prolly called Fae pointing upwards with the weight pointing downwards. Thanks

Homework Statement A parachutist relies on air resistance (mainly on her parachute) to decrease her downward velocity. She and her parachute have a mass of 55.0 kg and air resistance exerts a total upward force of 620 N on her and her parachute. A.) What is the weight of the parachutist? B.)...

I am lean by nature and an avid cyclist at that. I noticed that any food I eat gets put to work during my extended spinning session. I would like to gain some more muscle in my leg area to give me more power during hill climbing and accelaration in a race. I don't know what kind of muscles I...

Homework Statement A box with a height L, and a cross sectional Area A is floating between two fluids of densities p1 and p2. Determine the mass of the box using ho, h1, h2, p1, p2, and A. Homework Equations F= pVg The Attempt at a Solution In the file attached I drew my free...

Homework Statement A weight lifter (mass 75Kg) raises body's centre of mass by 0.4 in the process of lifting a barbell weight of 70kg to the height of 1.04m above the ground. Calculate the total work done in lifting the weight.The weight is raised in 0.2 seconds; hence calculate the power of...

Hi there, If there are 2 bicycle riders who use exactly the same type of bicycle, start at the same spot but one rider is 100kg and another rider is 50kg.. would the heavier rider coming down the slope faster than the lighter rider? basically, I just want to know if the weight would affects...

Homework Statement In a certain structure, the cables C1, C2, and C3 (Figure) can each carry a weight of 100kg, and C4, C5, and C6 can each carry 50kg. Weights are suspended at R, S, and T. What is the maximum total weight the structure can carry? PS1: (Ignore the weight of the...

You could gain a lot of weight and still have very little body fat! Of course, you'd need to do it for a very long period of time (for the D2O to replace all the H2O in your body). But would there be health risks? haha.

Homework Statement A compound with a molecular weight of 110.1 g that contained only C, H, and O was analyzed by combustion. the combustion of a 5.19 g sample of the compound resulted in the formation of 12.4 g of carbon dioxide and 2.55 g of water. What is the molecular formulas of this...

What formula would one use to determine the centrifugal force at the tip of a rotor of 35ft diameter, rotating at 392rpm? Would any other factors be necessary, such as blade thickness, weight, etc? A pilot I work with doesn't believe the weight at the rotor tip would be measured in tons. I...

I'm Canadian, and I'm trying to convert the draw weight (55lb-65lb) into something I can put into 1/2kx^2. Please help!

First off, please excuse my general lack of physics knowledge, it's been 10 yrs since one year of it in high school ... but I can usually follow along pretty well once pointed in the right direction. I've been curious about the relationship of wheel weight and diameter in relation to distance...

can someone help me with this. you have a free falling weight such as a 500 lb. steel ball dropping from 3 ft. How much force will the weight produce in ft. lbs. or tons when hitting the ground. what is the formula for figuring this. Also, will the amount of force double if dropped from 6 ft...

Hi all! I have a few questions about physics and weight training. I searched around a bit but only found these two threads: https://www.physicsforums.com/showthread.php?t=451027" https://www.physicsforums.com/showthread.php?t=381643" which don't totally cover my interests. I know that...

Homework Statement Steel object is pulling uniformly through the ice with applied force 2 Newtons. Find object's weight (P), if k of friction is 0.02 Homework Equations F = 2 Newtons k = 0.02 P - ? F = m*a P = m*g The Attempt at a Solution I drow all forces and made this: ma =...

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 A 500g mass is submerged in water, displacing 57.6mL of water. The force of gravity on the weight when submerged is measured to be 4.35N. The actual weight should be 4.9N. (remember that the density of water is 1000kg/m3) (the weight is being held in the water by a spring...

Homework Statement What is the apparent weight of a rock submerged in water if the rock weighs 58 N in air and has a volume of 1.8 * 10^-3 m^3? And then as a continuation: A rock weighing 57 N with a volume of 2.3 10-3 m3 is submerged in a liquid with a density exactly twice that of...

Hi all, when you try to lift explosively a weight there is a acceleration phase and obviously a deceleration phase in order to stop the weight at the end of range of motion(end of repetition). Is it alright to assume that at the deceleration phase less force than the weight is applied?

hey guys I am new here so i would first like to say thanks for reading my post. i got this question that I'm stumped on so please help me thank you! A *12 kg crate is sliding at constant speed down a smooth platform that makes a 35. degree angle* with the horizontal. Calculate the weight...

Imagine an object is resting upon the floor. The object is pushing the floor with a force mg, which is vertically downward. The floor is also pushing the object back with the same magnitude of force but it is vertically upward. My question is: which one of these force is called weight? My...

Homework Statement Say functions f and g continuous on [a,b] and happen to be orthogonal with respect to the weight function 1. Show that f or g has to vanish within (a,b). Homework Equations f and g are orthogonal w.r.t. a weight function w(x) if the integral from [a,b] of f(x)g(x)w(x)dx = 0...

Homework Statement Scenario: A block of mass m hanging on the end of a vertical spring with spring constant k Homework Equations When the spring has come to rest: Vertical eqm: weight = force exerted by spring mg = kx Energy conservation: loss in GPE =...

Homework Statement A man, holding a weight in each hand, stands at the center of a horizontal frictionless rotating turntable. The effect of the weights is to double the rotational inertia of the system. As he is rotating, the man opens his hands and drops the two weights. They fall outside...

Homework Statement I was just websearching and came across this interesting demonstration. http://demonstrations.wolfram.com/AMassiveBarOscillatingBetweenTwoIdenticalRotatingSupportRoll/ Homework Equations I wanted to define the normal forces N1 and N2 based on their position x(t) from...

weight or mass? I have a friend here who is totally convinced that the scales we use at home to weigh ourselves our actually measuring our mass not our weight...Could somebody please enlighten her hahaha