# Solve Force & Buoyancy: 1000N to Lift Concrete Block Out of Water

• srfrgrl727
In summary, To lift a concrete block from a fresh water lake to the surface, a force of 1000N is required. To lift it out of the lake completely, the force needed would be the buoyant force plus 1000N. The volume and density of the block would be needed to calculate the exact force required.
srfrgrl727
Can anyone help me out. I don't know of any equation that i can us eto solve this A force 1000N is required to raise a concrete block to the surface of a fresh wate rlake. what is the force required to lift it out of the lake. I know that i need to figure out what the weight outside of wate ris, but i don't know how. no i don't know the volume the 1000N is the only info given. density is 2320 kg/m3.

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If you draw a free body diagram of the block under water you should have three forces acting on it: The block's weight, the buoyancy force and the 1000N applied force. This should tell you that the force required to lift the block in air will equal the buoyant force + 1000N.

Do you know the volume of the block?

srfrgrl727 said:
no i don't know the volume the 1000N is the only info given.
But are you given the density of concrete?

The Force you need to raise the block with the volume $$V$$ to the surface is
$$F_1=gV(\rho_{concrete}-\rho_{water})$$
the force to raise the block futher is

$$F_2=gV\rho_{concrete}$$

Then $$\frac{F_2}{F_1}=$$

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## 1. How is force calculated in buoyancy?

Force in buoyancy is calculated using Archimedes' Principle, which states that the upward buoyant force acting on an object in a fluid is equal to the weight of the displaced fluid. This means that the force is dependent on the density of the fluid and the volume of the object.

## 2. Can buoyancy be used to lift heavy objects out of water?

Yes, buoyancy can be used to lift heavy objects out of water. In order to do so, the buoyant force acting on the object must be greater than the weight of the object. This can be achieved by increasing the volume of the object or decreasing the density of the fluid.

## 3. How much force is needed to lift a concrete block weighing 1000N out of water?

In order to lift a concrete block weighing 1000N out of water, a force equal to 1000N must be applied in the opposite direction of the buoyant force. This can be achieved by using a crane or other mechanical means.

## 4. What factors affect the buoyant force on an object?

The buoyant force on an object is affected by the density of the fluid, the volume of the object, and the depth at which the object is submerged. The density of the fluid and the volume of the object are directly proportional to the buoyant force, while the depth is inversely proportional.

## 5. Is the force of buoyancy the same as the weight of the object?

No, the force of buoyancy is not the same as the weight of the object. The weight of an object is the force of gravity acting on it, while the buoyant force is the upward force exerted by a fluid on an object. These forces may be equal in magnitude, but they act in opposite directions.

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