Physics 11th Chap 6 : Topic 1 - Maryam Publications

Physics Chapter 6 : Topic 1

Archimedes’ Principle and Flotation

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According to Archimedes’ principle, a body immersed in a fluid experiences an upward force equal to:

A) Weight of the displaced fluid

B) Volume of the body

C) Weight of the body

D) Mass of the displaced fluid

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The upward force exerted by a fluid on an immersed object is called:

A) Buoyant force

B) Frictional force

C) Centripetal force

D) Gravitational force

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The SI unit of buoyant force is:

A) Pascal

B) $\mathbf{kg\ /\ m}^{\mathbf{3}}$

C) Joule

D) Newton

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The buoyant force acting on an object depends on:

A) Volume of displaced fluid

B) Colour of object

C) Weight of object only

D) Shape of object only

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Archimedes’ principle is based on the concept of:

A) Heat transfer

B) Pressure difference in a fluid

C) Electric charge

D) Conservation of momentum

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The apparent weight of an object submerged in water is:

A) Equal to its actual weight

B) Less than its actual weight

C) Greater than its actual weight

D) Always zero

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The relation between actual weight and apparent weight is:

A) Apparent weight $\mathbf{=}$ Actual weight $\mathbf{+}$ Buoyant force

B) Actual weight $\mathbf{=}$ Apparent weight $\mathbf{+}$ Buoyant force

C) Actual weight $\mathbf{=}$ Apparent weight $\mathbf{-}$ Buoyant force

D) They are unrelated

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A stone feels lighter when submerged in water because:

A) Water provides an upward buoyant force.

B) Its volume decreases.

C) Gravity becomes weaker.

D) Its mass decreases.

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If the buoyant force equals the weight of an object, the object will:

A) Move downward with acceleration

B) Float in equilibrium

C) Sink

D) Have zero mass

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An object completely immersed in water displaces:

A) No water

B) Water equal to its mass

C) Water equal to its weight

D) Water equal to its volume

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The law of flotation states that a floating body displaces fluid whose weight is:

A) Zero

B) Less than the body weight

C) Greater than the body weight

D) Equal to the body weight

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A floating object remains at rest because:

A) Gravity is absent.

B) It has no mass.

C) Buoyant force balances its weight.

D) Water has no pressure.

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A ship floats on water because:

A) Steel is lighter than water

B) Gravity does not act on ships

C) Water pushes downward

D) The average density of ship is less than water

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When a floating object is loaded with more weight, it:

A) Sinks deeper

B) Leaves the water

C) Has no change

D) Rises higher

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A floating object displaces water equal to:

A) Half its volume always

B) Its submerged volume only

C) Zero volume

D) Its total volume always

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An object floats in water when its density is:

A) Less than water density

B) Greater than water density

C) Infinite

D) Equal to air density

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An object sinks when:

A) Density is zero.

B) Weight is greater than buoyant force.

C) Both forces are equal.

D) Buoyant force is greater than weight.

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If an object has the same density as the fluid, it will:

A) Remain suspended in fluid

B) Float completely above fluid

C) Produce no buoyant force

D) Sink immediately

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Ice floats on water because:

A) Ice has lower density than water.

B) Gravity does not act on ice.

C) Water has no pressure.

D) Ice has greater density than water.

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A body displaces $\mathbf{0.02\ m}^{\mathbf{3}}$ of water. If water density is $\mathbf{1000\ kg/m}^{\mathbf{3}}$, buoyant force is:

A) $\mathbf{196\ N}$

B) $\mathbf{2000\ N}$

C) $\mathbf{100\ N}$

D) $\mathbf{20\ N}$

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A floating object weighs $\mathbf{500\ N}$. The buoyant force acting on it is:

A) Zero

B) $\mathbf{1000\ N}$

C) $\mathbf{250\ N}$

D) $\mathbf{500\ N}$

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A metal ship floats while a metal nail sinks because:

A) Nail has no mass.

B) Ship has greater average volume and lower average density.

C) Ship has no weight.

D) Water does not exert force on ships.

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An object has mass $\mathbf{5\ kg}$ and volume $\mathbf{0.002\ m}^{\mathbf{3}}$. Its density is:

A) $\mathbf{10000\ kg\ /\ m}^{\mathbf{3}}$

B) $\mathbf{250\ kg\ /\ m}^{\mathbf{3}}$

C) $\mathbf{2500\ kg\ /\ m}^{\mathbf{3}}$

D) $\mathbf{5000\ kg\ /\ m}^{\mathbf{3}}$

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A body weighs $\mathbf{100\ N}$ in air and $\mathbf{70\ N}$ in water. The buoyant force is:

A) $\mathbf{170\ N}$

B) $\mathbf{100\ N}$

C) $\mathbf{70\ N}$

D) $\mathbf{30\ N}$

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A floating body displaces $\mathbf{3\ kg}$ of water. Its mass is:

A) $\mathbf{3\ kg}$

B) $\mathbf{1\ kg}$

C) $\mathbf{6\ kg}$

D) $\mathbf{9\ kg}$

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Submarines rise and sink by changing:

A) Their mass only

B) Their volume and average density

C) Water pressure only

D) Gravity

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Hydrometers work on:

A) Ohm’s law

B) Newton’s laws

C) Bernoulli’s principle

D) Archimedes’ principle

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A life jacket helps a person float because it:

A) Decreases average density

B) Stops buoyant force

C) Increases body weight

D) Removes gravity

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A balloon rises in air because:

A) Air has no mass

B) Pressure becomes zero

C) Buoyant force exceeds its weight

D) Gravity stops acting

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The stability of ships depends mainly on:

A) Colour of ship

B) Centre of gravity and buoyancy

C) Temperature only

D) Speed only

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If a floating object is pushed deeper into water, the buoyant force:

A) Becomes zero

B) Increases until equilibrium is restored

C) Decreases

D) Remains unchanged always

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A completely submerged object has buoyant force depending on:

A) Shape only

B) Depth only

C) Colour only

D) Volume and fluid density

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If the density of liquid increases, the buoyant force on an object:

A) Becomes zero

B) Does not change

C) Increases

D) Decreases

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A person weighs less in water because:

A) His mass decreases

B) Gravity disappears

C) Water provides an upward force

D) His volume decreases

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The condition for floating equilibrium is:

A) Weight $\ \mathbf{= \ }$ buoyant force

B) Weight $\ \mathbf{>}\ $ buoyant force

C) No forces act

D) Weight $\ \mathbf{<}\ $ buoyant force

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Archimedes’ principle can be applied to:

A) Solids only

B) Liquids only

C) Gases only

D) Both liquids and gases

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