Archimedes Definition and 211 Threads

Hi, I'm watching a talk about Archimedes Law of the lever, and I was wondering: Does anyone know how the formula d=w/2w/b-a) was derived from the lecture drawing at 9.00 min in? The speaker just skips the algebraic derivation.

Homework Statement Homework EquationsThe Attempt at a Solution On integrating the force due to fluid pressure on the cap , I have arrived at the correct result ##ρgπR^2(H-\frac{2}{3}R)## . This in turn would be the force with which the cap presses the bottom. But I would like to solve this...

Greetings, I have a question about the classic Archimede's principle. A ball inflated with air will not sink into water. My understanding is that it will be pushed from all directions by the surrounding water trying to fill the space occupied by the ball. So there will be a pressure downwards...

And what are the methods? This was stimulated by This question could be rephrased as "use the method for finding square roots you were taught in school to find √7 to 6 decimal places". If you were taught at school. If you were not taught at school you were luckier than me, I was. It has had...

A solid weights 260N in air, 240N in water of a fluid density 1000kg/m^3, and 250N in oil Determine the relative density of the solid and of the oil I think I have already worked out the density of the solid: Weight of water displaced = 260N - 240N = 20N 20N / 9.8 = 2.0408kg Water density...

Homework Statement I have confusion. Suppose i have metal cube placed in empty vessel. I have seal tight the base of cube so that the water or any fluid can't seep below the cube. Now i pour water into the vessel. Will there be bouyancy on the metal cube ?? If i measure the weight of cube, will...

It has been eons since I've done any trigonometry, but I just can't prove how this following relationship holds for $n = 4, 8, 16, 32, \dots$ The relation is: $$ 2 \biggl( \! \frac{A_{2n}}{n} \! \biggr)^2 = \, 1 - \Biggl( \sqrt{1 - \frac{2A_n^{\phantom{X}}}{n}} \, \Biggr)^{\!2} $$ I've subbed...

Homework Statement given a lever and a place to stand, Archimedes claimed to be able to move the earth. amusing he could use the moon as a privet point, how long would the lever have to be? (the Earth moon distance is 382000km Homework Equations toque = (force)(lever arm) toque =I cross alpha...

Homework Statement A small boat weighing 1000 N has a surface area of 3 m^2. It floats only 5 cm above the water level when in a fresh-water lake. How high out of the water will it ride in a salt-water lake? Assume the surface area of the boat does not change as it rises (salt water has a...

Homework Statement A man decides to make some measurements on a bar of gold before buying it at a cut-rate price. He find that the bar weighs 2000 N in air and 1600 N when submerged in water. Is the bar gold? Homework Equations B = density* V* g The Attempt at a Solution I tried to use the...

Homework Statement Question: What minimum volume must a slab of ice in a freshwater lake have for a 50.0kg woman to be able to stand on it without getting her feet wet? Homework Equations Archimedes principle...

Homework Statement A rod 6 meters in length has specific gravity 25/36. One end of the rod is tied to a 5 meter rope, which in turn is attached to the floor of a pool 10 meters deep. Find the length of the part of rod, which is out of water. The answer is 1 meter. Homework Equations...

Hello; I have been toying with the idea of creating an Archimedes pump using PVC and 6 inch drainage pipe. The idea is that by using tubing coiled around a PVC core, and rotating it using torque on PVC collars, as long as the pump is angled correctly, and friction is sufficiently low (the...

Homework Statement A 100g object having a density less than that of water is placed into a beaker half full of water. The beaker is then placed on a triple beam balance. Would be measured weight be equal to, greater than, or less than the weights of the water, the beaker, and the object added...

Homework Statement A cylindrical log of uniform density and radius R=30.0cm floats so that the vertical distance from the water line to the top of the log is d = 12.0cm. What is the density of the log? Homework Equations Fbouyant=Wwaterdisplaced ρwater * V displaced water = ρlog *...

The title pretty much says it all, what do we have today that is better than Archimedes 'method of exhaustion' (although I would argue it is quite beautiful) for deriving Pi?

Homework Statement A hot air balloon with V = 500 m^3 is floating in the air without moving. The air outside the balloon has a density of 1,20 kg/m^3, and the hot air inside the balloon has a density of 0,75 kg/m^3. Calculate the total mass of the hot air balloon. Homework Equations...

Homework Statement We have a chinese lantern (balloon) made of paper, cylinder shaped with the following sizes: base diameter - 45 cm, height - 70 cm. Mass of the balloon is 57 g (21 g from this is mass of "fuel" - the fuel is wax paper!). Fuel is then ignited at the centre of the base, which...

Homework Statement A block of wood floats in fresh water with 0.722 of its volume V submerged and in oil with 0.895 V submerged. Find the density of (a) the wood and (b) the oil. Homework Equations mass = density x volume f = ma conservation of mass F_{weight} - F_{buoyancy} =...

If we have an upward moving sphere with 0.4 m3 volume and 100 kg mass , according to Archimedes buoyancy force = 4000 N so acceleration = 40 m/s^2 But according to Atwood's principle , buoyancy force ≈ 1600 N acceleration = 16 m/s^2 what makes such big difference . ( ignore drag force and...

Archimedes principle of the force of upthrust = weight of water displaced by the body immersed , but is this law independent of the shape of this body. If we use the idea that the upthrust = P*A on the lower side - P*A on the upper side , if we use it on a rectangle or a square , the only change...

Well it's physics and current so I guess this is the place for it. London especially the City area is changing fast by new construction; you would notice if you hadn't been for a few years, even one or two. In a new construction apparently the architects didn't think of the focussing...

I want to know why does the buoyant force equal to the weight of fluid displaced and how the weight of water displaced is equal to the weight of object for free floating objects? What's buoyant force by the way?

Hi to all, i will appreciate your help in this. This is the situation: I have a tank, with a water column in it. This tank at the bottom has an "ideal" seal (a seal that permit the passing of object from bottom to upwards, but not the water to fall down.) In this system i have sphere with...

A geode is a hollow rock with a solid shell and an air-filled interior. Suppose a particular geode weighs twice as much in air as it does when completely submerged in water. If the density of the solid part of the geode is 3100 km/m^3 , what fraction of the geode's volume is hollow? The...

Could I please be explained this problem as I simply can't do it... Archimedes has a bath which is filled using three taps labelled A, B and C. The rates of flow of B is twice that of A, the rates of flow of C is three times that of A. Yesterday, Archimedes filled his bath as follows...

Homework Statement Legend has it that Archimedes first used his discovery to help out his boss King Hero of Syracuse. The king had given 700g of gold to a goldsmith to make him a crown. When the goldsmith brought him the finished crown the King was suspicious that he had defrauded him by...

If I have a body (for simplicity a cube with side d) on a fluid (with density ρ) with its top at a depth h, the force acting on top of it is ma = (h*d*d)*ρ*(g); where g is the acceleration of gravity, (d*d*h) is the volume of the column of liquid on top of the cube and that times ρ is the mass...

Hello, I was taking a shower and started to think about balloons and helium and this question came to me: Wouldn't the things on Earth be lighter than say, a similar planet (same gravity) but with no atmosphere? (because of the push from air) I googled it but I am not sure of using the correct...

Hello everyone, I'm beginning a research project for a Math History class on Archimedes. Since technically it is a math class, I have to demonstrate and explain some of his math. Naturally, I can't explain and go into detail on everything the man did, and having only about a month to prepare...

Hello! My physics teacher gave me an assignment to work out (theoretically) how Millikan's oildrop experiment works. The simple principle of the experiment (as far as I know): E = \frac{F}{Q} F = mg mg = qE \rightarrow q = \frac{mg}{E} However, after reading a bit on Wikipedia it...

Homework Statement Find the curvature of the spiral of Archimedes r = 2θ Homework Equations ||v x a || / ||v||^3 The Attempt at a Solution I tried to convert the polar equation into parametric and got x = 2θsinθ y = 2θsinθ z = 0 I think took the derivative of x y and z...

Homework Statement 1. a 300kg object is placed upon a block of ice what volume of ice is needed to keep the object fully above water. 2. if the object density is .94gcm ^-3 what volume of the object remains above water on ice half the size. 3. What volume of the object remains above water...

Hi, I'm an engineer designing a spring system for a garage roller door. I need to know the number of turns of the door for all the size combinations. I've found this page which gives a good equation for finding the length if you know the number of turns, starting radius and gap between...

Homework Statement It`s not to calculate, actually, I am just trying to understand this. I think it has to do with Archimedes Principle, but could anyone explain the following more clearer to me? "It`s observed that as bubbles rise in a deep column of water, the diameter of the bubbles...

Homework Statement This is the information and calculations I have been given, but am not sure it is correct. Please verify. An object in the form of a cube with sides of 50 cm is immersed in water. Determine the height of immersed object, knowing that the density of water is 1000 kg/m^3 and...

Archimedes' Principle states: "Any object, wholly or partially immersed in a fluid, is buoyed up by a force equal to the weight of the fluid displaced by the object." If this is true, why then, when you take a bowling ball and submerge it in water, and take a rubber ball of the same size and...

The weight in the air of the crown and the piece of solid gold is the same 1) If the crown is made of gold and silver (density is less than that of the gold) is the apparent weight of the crown in water greater than, equal to, or less than that of the solid gold? Why? 2) What if the crown...

Hi guys. I'm *attempting to make* an archimedes screw for my engineering project. The only stipulations for this project are as follows: Create a machine that will move water from point A to point B The machine must be powered by my professor's desk fan. So, I bought a small wooden...

Why isn't the influence of air pressure assimilated in Archimedes law? If an obect is more dense than the fluid, it wil sink. That is clear, but suppose I could lower down de air pressue, so less force that tends to push the object tot the surface. Is there any situation possible of adjusting...

Hi :) When I have a container with water and put a piece of metal down in the water while it's hanging on the string, I know that there will be two forces pulling it upwords: B = δVg and the string force T But the force pulling it down, is that the gravitation? Or is it a force that...

We are preparing a physcs quiz and are planning to use the following problem If we have a wooden block balanced at the junction of two immiscible liquids then we have the buoyancy of the two liquids balance the weight of the block.The lower liquid will exert your normal upthrust but the upper...

Homework Statement A solid cube of foam plastic has a volume of 25m^3 and a density of 800kg/m^3. How large a force is required to hold it under water? Homework Equations P = F/A Fb = ρgV ρ = m/V The Attempt at a Solution ρ = m/V 800 = m / 0.000025 m = 0.02kg so F = mg = 0.02...

I'm really confused about the buoyant force. What I've understood is that the buoyant force of an object is equal to the volume of the displaced fluid even if it is floating (not fully immersed in the fluid). How can this be possible? The volume of the object is the amount of water displaced...

the Archimedes' Principle states that the weight of the fluid displaced is equal to the buoyant force. why/how does that happen?

A sphere of density = 500 kg/m^3 floats on water (density of water = 1000 kg/m^3). 1. What fraction of the volume of the sphere is below the waterline? ---I understand this problem and I got the correct answer of 0.5 2. Another liquid of density 200 kg/m^3 is now added on top of the water. The...

Homework Statement A piece of metal weighs 50.0 N in air, 36.0 N in water and 41.0 N in oil. Find the densities of the metal and the oil.Homework Equations Density of Water is 1000 kg / m^{3} Density of Air is 0.00121 g / cm^{3}The Attempt at a Solution I really don't have any idea on how to...

Homework Statement Consider a submarine inside an ocean. It's bottom is flat and upper portion is hemispherical. It is settled at the bottom of the sea. What should direction of Boyant force. Upward or downward? Now by the external agent the submarine is lifted a bit up. Now it is not touching...

Homework Statement A solid sphere of mass m=2 kilogram and specific gravity s=0.5 is held stationary to a tank as shown in figure. The tank is accelerating upward with a=2ms-2. calculate the tension in the string? If suddenly string break then the acceleration of the ball in frame of tank...

Homework Statement A Kennedy half-dollar has a mass that is 1.150 x 10-2 kg. The coin is a mixture of silver and copper, and in water weighs 0.1011 N. Determine the mass of silver in the coin. Homework Equations Explicit givens: m = 1.150 x 10-2kg apparent weight =...