Buoyant Force

Q.

For a floating body, how is its weight related to the buoyant force?

Q.

The magnitude of buoyant force on a body of fixed volume when submerged completely depends on

1. Density of liquid

2. Density of body

3. Weight of body

4. None of these

Q.

Name the two factors that affect the buoyant force.

Q.

The fundamental frequency of a sonometer wire is $n$. If the length and diameter of the wire are doubled keeping the tension the same, then the new fundamental frequency is

1. $\frac{2n}{\sqrt{2}}$

2. $\frac{n}{2\sqrt{2}}$

3. $\sqrt{2}n$

4. $\frac{n}{4}$

Q. A body floats with 2/5 th of its volume above the surface of water. Calculate the density of the material of the body in gcm^{​​​​gcm-3}

Q.

Define Floating.

Q.

Explain why it is easier to lift a stone under water than in air.

Q.

It is easy to pull the bucket as long as it is inside water, but as soon as it starts coming out of the water, it appears to become heavy because of

1. upthrust

2. the change in density of the bucket in water.

3. the surface tension of water.

4. the viscosity of water.

Q.

How is the bouyant force related to the density of liquid

Q.

A body immersed in a liquid appears lighter than it really is. Explain.

Q.

While drawing water from a well with a bucket the bucket of water appears to be lighter when it's under water is than when it's out of it . Give reason

Q. A cork is floating on the surface of water. The buoyant force acts in the direction.

1. upward
2. downward
3. parallel

Q.

A solid weighs $50N$ in the air and $45N$ when completely immersed in water. Density of water $\rho$ = $1000kg/m^3$. Calculate the volume of the solid.

(Take acceleration due to gravity = $10m/s^2$)

1. 
2. 
3. 
4. 

Q.

A piece of sealing wax weighs $0.27kgf$ in air and $0.12kgf$ when immersed in water. Calculate its:

1. relative density, and
2. apparent weight in a liquid of density $800kg/m^3$

Q. The upward force acting on an object submerged in a liquid is called:

1. Buoyant force
2. Magnetic force
3. Gravitational force
4. Frictional force

Q.

A stone of density 3000 kg/m³ is lying submerged in water of density 1000 kg/m³, if the mass of stone in air is 150 Kg, calculate the force required to lift the stone. Take g = 10 m/s²

Q.

A bucket of water of $50kg$ is raised from a depth of $100m$ to the ground by a rope. The mass of the rope is $1kg$ per meter what is the work done?

Q.

Describe an activity to verify the Archimedes' principle.

Q.

Write three phenomena which can be explained with the help of Newtons law of gravitation.

Q. Buoyant force is an upward force that is equal to the weight of the fluid it __.

1. displaces
2. generates
3. overcomes
4. holds

Q.

A block of silver displaces 200 ml of water in a measuring cylinder. If the density of silver is 10300 kg/$m^3$, find the mass of block.

Q.

When an object is immersed in a fluid, which of the following forces will act on the object?

1. Gravitational force

2. Buoyant force

3. Both A and B

4. Frictional force

Q.

What happens to the weight of a body when it is immersed in a liquid.

1. Remains the same.

2. It will decrease.

3. It will increase.

4. It will increase first and then decrease.

Q.

A body experiences the same buoyant force when it floats and sinks in water.

1. True

2. False

Q.

Because buoyant force act in a direction opposite the force of gravity the net force acting on an object submerged in a fluid such as water is smaller than the objects weight.

1. True
2. False

Q.

Differentiate between flotation and sinking.

Q.

The value of G (gravitational constant) depends upon____

1. The mass of the two bodies

2. The distance beween the two bodies

3. none of these

4. the medium between 2 bodies

Q.

A sphere of iron and a block of wood having the same volume are held under water. Which of these will experience a greater buoyant force?

1. Wooden block
2. Iron sphere
3. Both A and B
4. Can’t be determined

Q.

A body of mass $m$ is immersed in water with $3/4th$ of volume outside of water. Buoyant force acting on it is $1000N$. Total volume of body is

( Take density of water as $1000kg/m^3$ and accelaration due to gravity as $10m/s^2$)

1. $1m^3$

2. $0.8m^3$

3. $10m^3$

4. $0.4m^3$

Q.

A body would experience greater buoyant force in a liquid whose density is (assume that the body is fully submerged)

1. $5g/c{m}^3$

2. $1000Kg/m^3$

3. $13.6g/c{m}^3$

4. $800g/c{m}^3$