Buoyant force Definition and 144 Threads

Homework Statement A cubic meter of some material has a mass of 8600 kg. The block of material is lowered into a lake by a strong cable until the block is completely submerged. Find buoyant force on the block. Homework Equations Fb= p x V x g. p= density of fluid, density of water...

Homework Statement A cubic meter of some material has a mass of 8600 kg. The block of material is lowered into a lake by a strong cable until the block is completely submerged. What is the buoyant force on the block? Homework Equations Fb=p x V x g. P= density of fluid, density of...

Hi, I'm having trouble with a conceptual problem: Homework Statement There is a block of wood in a jar with water; it is floating. If I pour oil into the container, obviously the oil sits at a layer above the water. The wooden block touches the water, oil and air now. Did the volume of the...

Hello, This is bugging me so I'd appreciate any help. I have two objects made from the same material with the same mass. The base of Object 2 is 3 times that of Object 1. If I place the objects base first in a liquid, why is the buoyant force on them equal? What here is what I'm...

Homework Statement Consider a ship that is floating in fresh water. The bottom of the ship is a depth of (df) below the surface. If the same ship is floating in sea water, the bottom of the ship (ds) below the surface. Given that the density of sea water is greater than the density of fresh...

Hi everyone, This question is killing me, I don't know why but I just can't get my head around it. Homework Statement A team of 6 scouts plans to cross a lake on a raft they designed. The scouts have wooden beams with an average density of .80. The beams measure 30cm x 30cm x 3m. The...

Homework Statement A cube, with a volume of 0.78 m3 is submerged in a swimming pool. What is the buoyant force acting on the object if it has a mass of 328 kg? Homework Equations The Attempt at a Solution

According to Newton 3rd law, every action will have a reaction. but how about buoyant force? if the buoyant force is the force of water on object then the reaction force will be the force of object on water. but is it other name for this force? thanks for reply.

Homework Statement I attached the original problem and a diagram I made with the variables on it. Basically we have a rod hanging from a wire at an angle theta with tension and the other end floating in water. So there is T=tension, weight=w=mg and buoyant force=F_b. I introduced symbols for...

Homework Statement I'm doing a problem that is likely a common one. It is comparing the buoyant force of an object in seawater to that of the same object in freshwater. which has more buoyant force acting on it? Homework Equations not sure of equations at this stage, and we are just...

A 1.2 kg block is pushed beneath the water and held there. What is the buoyant force (in N) acting on the block? (a) not enough information to answer (b) 11.76 (c) 1.2 (d) 14.56 (e) none of these Since buoyant force is equal to the wt of the water displaced, I used the equation w=mg...

Homework Statement Homework Equations density = mass/volume FB = rhoo vog for a floating object F = mg The Attempt at a Solution Buoyant force = force of gravity due to the board rhoo vo = m vo = area*height submerged vo = 2.4*.05 vo = 0.12 m^3 volume of the board =...

if we weigh a metal object which is immersed in water, we have to correct the buoyant force for water. Air is a fluid. Why don't we correct for the buoyant force of the air when we weigh it in the air? What i think it may be is because we have a set atmospheric pressure being 1.013 Kpa in...

Homework Statement A block of copper having a density of 8.90 g/cm^3 has an apparent mass 120g in water and 116g when submerged in a liquid. What is the density of the liquid? Homework Equations The Attempt at a Solution Don't know if there's a better method, but here is the way I did it...

couple question regarding buyoancy and water displacment 1. so if you have a pond w/ ρ=1.2 and part of the water in that pond turns into ice will the level decrease increase stay the same? (i think it will stay the same) 2. same pond w/ a ρ=1.2 and you add ice cubes w/ a ρ= 1.2 the cubes...

And does air resistance depend upon surface area?

Hi I want to make sure my intuition is correct about the buoyant force. What I am confused by if we take a cube or some sort of object and its submerged at height H1 as in picture I uploaded,then their will be a force of P1 * A; in case of the cube it's it would be d^2. What I don't understand...

Homework Statement An aluminum block has a mass of 0.25kg and a density of 2700 kg/m cubic. a) calculate the volume of the aluminum block. b) Determine the buoyant force exerted on this block when it´s completely submerged in water of density 1000kg/m cubic. Homework Equations v = m/d The...

Buoyant force of air negligible?? Why are we justified in assuming that the buoyant force on an object in air is generally negligible. Can you please explain using some example equations? Many thanks.

Given two objects of identical density and weight, one is floating on water and the other is floating on saltwater. Is the magnitude of buoyant force acting on the object the same in the two situations? From my thinking, it seems that the weight of the object in the the two situations should not...

Homework Statement Two cubes made of the same material and edge length 'a' and '2a'. They are placed in a liquid of density σ such that the larger cube is completely submerged when the smaller cube is placed on top of it and the lower surface of smaller cube is just touching the surface of...

Homework Statement A less-dense liquid of density ρ1 floats on top of a more-dense liquid of density ρ2 . A uniform cylinder of length l and densityρ, with ρ1< ρ<ρ2, floats at the interface with its long axis vertical. What fraction of the length is in the more-dense liquid? Homework...

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...

I am just not too sure how to start this equation. The answer was given (i.e. Vc = 3698 cm^3), but I just need to know the steps on how to get to the answer. A sand core used to form the internal surfaces of a steel casting experiences a buoyancy force of 225.63 N. What is the volume of the...

1. A juniper wood plank measuring 7 ft by 0.5 ft by 0.1 ft is totally immersed in water. What is the net force acting on the plank? () 2. a) F top = P top * A top(l x w) ; b) P bottom = P top + (Dw * h); c) F bottom = (F top) + (Dw*l*w*h); d) Fb = F bottom - F top e) Weight = Dw * l * w...

Why is the fluid's density taken in the buoyant force? If the system is in equilibrium, then isn't the buoyant force compensating for the weight of the object? In such a case, shouldn't the density of the object be considered? Please help!

Homework Statement When a beaker partially filled with water is placed on an accurate scale the scale reads 22.0 g. If a piece of metal with a density of 3.800 kg/dm^3 and volume of 2.40 cm^3 is suspended by a thin string so that the metal is submerged in the water does not rest at the bottom...

Homework Statement A cube of metal(density=6.00 kg/dm^3) has a cavity inside it. It weighs 2.40 times as much in air as it does when completely submerged in water. What fraction of the cube's volume is the cavity? Homework Equations Density=m/v Fb=Density of fluid times volume of fluid...

Homework Statement A solid cube of unkown material is floating upright in water so that 1/4 of the cube is above the surface of the water. What is the density of the material? Homework Equations Density=m/v F=mg Fb=density of fluid times volume of the fluid times g P=density times...

Homework Statement A downward force of 18.0 N must be applied to a woman weighing 480.0 N to keep her completely submerged in water. What is the density of her body Homework Equations Density=m/v Fb=density of fluid times volume of fluid times g Fb=F(bottom) minus F(top) The Attempt...

Homework Statement A block of foam plastic has a volume of 25.0 cm^3 and a density of 0.800 g/cm^3. How large a force is required to hold it under water? Homework Equations F=mg, m=density times volume The Attempt at a Solution I first converted 25.0 cm^3 into 2.5 times 10^-5m^3 and...

Homework Statement 1) A 0.0200 kg metal(density=4.000 g/cm^3) object is suspended from a thead and is submerged in a jar of oil(density=1.500 kg/dm^3) What is the apparent weight in the thread) For this one I keep doing this one but I think I am getting it wrong because of my conversion...

Rank the buoyant forces exerted on the following five objects of equal volume from the largest to the smallest. Assume the objects have been dropped into a swimming pool and allowed to come to mechanical equilibrium. If any buoyant forces are equal, state that in your ranking. (Use only ">" or...

Homework Statement a cylinder is in a deep pool of liquid. it has mass 2kg, diameter 10cm, height 15cm. the density of the liquid is 1.5g/cm^3. The cylinder is submerged up to 12cm, and let go. Show that the resulting motion is simple harmonic. Homework Equations x=Acos(wt)...

Homework Statement A hot air balloon experiences an acceleration of 110 m/s2 [down]. The total mass of the balloon is 315kg What is the buoyant force of the system? aballoon = 110m/s2 agravity = 9.8m/s2 mtotal = 315Homework Equations Fgravity = 315 * 9.8 = 3087 Fnet = 315 * 110 = 34650The...

An flying object needs lift,but this lift is like buoyant force in air?? just like when any object is immersed in water it feels lighter because a net upward force is acting on it same way do net upward force is acted by air when any object is flying in air?? and that net upward force is more...

Homework Statement Your local king has asked you to determine the density of a crown. If you suspend it from a spring scale, the scale reads 8.33 N. If you then lower the statue into a tub of water, so that it is completely submerged, the scale reads 7.81 N. What is the density of the...

Homework Statement Two objects made from the same material with the same mass are placed in a liquid, base first. The base of Object 2 is three times that of Object 1. What best describes the buoyant force on the objects? A) Object 1 has a greater buoyant force acting on it because it...

Homework Statement Bozo the clown brings an empty birthday balloon with a mass of 0.0120 kg to your party. Bozo fills the balloon with helium of density 0.181 kg/m3. The filled balloon is a perfect sphere with a radius of 0.500 m. Bozo ties the balloon to a rope and holds is so that it is...

1. a)Homework Statement What is the buyant force on 0.90kg of a block of ice floating on liquid water? B) What is the buyant force on 0.90kg of ice held completely submerged under water? Homework Equations Fbuy+mg=0 Fb=mg The Attempt at a SolutionFb=.90kg * 9.18m/s^2=8.8 so i...

a metal ball weighs 1 N in air and 0.8 N when totally immersed in water. find magnitue of upthrust force.

I am interested in determining if a method can be devised to create a safe zone for humans to be accelerated at very high G force. I watched a very interesting experiment where a water filled balloon was submerged in container of water and had 60 g's of force applied via a centrifuge. The...

Homework Statement The buoyant force on a balloon is equal to the mass of air it displaces. The gravitational force on the balloon is equal to the sum of the masses of the balloon, the gas it contains, and the balloonist. If the balloon and balloonist together weight 175 kg, what would the...

I have been pondering about this for awhile now. If there are rocks on a boat (that's floating in a water) and one by one the rock is thrown onto the water. Does the water level rise or fall from the initial level? I believe that it will rise but am not 100% sure.

Homework Statement A 6500-kg iceberg with density 931kg/m^3 is afloat in seawater with density 1030kg/m^3. a) Find the buoyant force on the iceberg b) the volume of water displaced by the iceberg c) The fraction of the icebergs volume that is below the waterline. Homework Equations Fb...

1.) 1 m3 object is floating in water. A third of the object is submerged. How much does the object weigh? 2.) Consider a floating hollow plastic box that has negligible mass. The volume of the box is 0.002 m3. If a 3.5 kg piece of copper is placed in the box, will the box sink or...

Consider two cubes: a copper cube (Density = 8.96 g/cm3 and a lead cube (Density = 11.4 g/cm3 that both have an edge length of 3.0 cm Calculate the magnitude of the buoyant force (in Newtons) acting on the copper cube and the lead cube when each is fully submerged in water. Show your work...

Homework Statement Suppose a buoy is made of a sealed steel tube of mass 5 kg with a diameter D = 7 cm and a length of 6 meters. At the end of the buoy is a spherical weight of galvanized steel (specific gravity=7.85). If the buoy floats in fresh water, what must be the mass of the steel M...

Homework Statement I'm trying to find the buoyant force on a hot air balloon. The mass of the displaced fluid is 2800 kg and the acceleration is that of gravity, (let's say 10 m/s^2). Homework Equations F=ma The Attempt at a Solution I think that you can just multiply these...

What's the direction of the buoyant force? I'm trying to find the equation for the charge on the Millikan oil drop experiment. It requires two equilibrium equations but I'm not sure which sign should the buoyant force have. My internet searches neither my book have been able to answer this...