Tag: physics

Questions Related to physics

A body of mass 400 g has a volume of 300 cm$^3$. Will body sink in water or not? [Density of water = 1000 kg/m$^3$]

archimedes' principle fluid pressure properties of matter physics

  1. Sink

  2. Float

  3. Sink partly

  4. Float partly

Show answer
Correct Option: A
Explanation:
Given :     Density of water     $\rho _w = 1000$ $kg/m^3  = 1$ $g/(cm)^3$
Density of body        $\rho _s = \dfrac{M}{V} = \dfrac{400}{300} = 1.33$  $g/(cm)^2$
$\implies$     $\rho _s >\rho _w$
Thus the body will sink in water.

A slid floats in a liquid in a partially dipped position.

archimedes' principle fluid pressure properties of matter physics

  1. The solid exerts a force equal to its weight on the liquid

  2. The weight of the displaced liquid equals the weight of the solid

  3. The liquid exerts a force of buoyancy on the solid which is equal to the weight of the solid

  4. The weight of the dipped part of the solid is equal to the weight of the displaced liquid

Show answer
Correct Option: A,B,C
Explanation:

The force that solid exerts on liquid is its weight. Hence option A is correct.
Since the solid is stationary, the weight of solid is equal to the force exerted on it by liquid.
According to Archimedes' Principle, the buoyant force acting upwards on the solid is equal to the weight of the liquid displaced. Hence option B and C are correct.

A balloon lifting in air follows:

archimedes' principle fluid pressure properties of matter physics

  1. Law of gravitation

  2. Archimedes principle

  3. Laws of motion

  4. all of the above

Show answer
Correct Option: D
Explanation:

In a lifting balloon, force of gravitation acts downwards as on all other materials present on the earth, given by $mg$.

Also Archimedes' principle acts on the balloon to provide a buoyant force $V\rho g$ upwards, and greater in magnitude than the gravitational force downwards. (Where $\rho$ is the density of air)
Hence Newton's law of motion provides the acceleration of the balloon upwards, given by: $ma=V\rho g-mg$

When a body is wholly or partly immersed in a liquid it experiences. 

archimedes' principle fluid pressure properties of matter physics

  1. An up-thrust or down-thrust depending on the density of the liquid

  2. An up-thrust

  3. A down-thrust

  4. None of the above

Show answer
Correct Option: B
Explanation:

Whenever a body is wholly or partially immersed in a liquid it experience an upthrust or buoyant force.

The principle on which Hare's apparatus works on is.

archimedes' principle fluid pressure properties of matter physics

  1. Bernoulli's principle

  2. Archimedes principle

  3. Newton's law

  4. Kepler's law

Show answer
Correct Option: B
Explanation:

Hare`s apparatus is used  to compare the densities of two liquids and is base on Archimedes principle .

so option (B) is correct

The upward thrust exerted on the body by the liquid acts vertically upwards through the center of gravity of the displaced liquid.

archimedes' principle fluid pressure properties of matter physics

  1. True

  2. False

Show answer
Correct Option: A
Explanation:

when a body is immersed in a fluid an downward force mg acts on it and to balance this force an upward force kown by the name buoyant force is exerted by the fluid .

so given statement is true , hence option ( A) is correct

A body is floating in a given liquid with half of its volume above the surface of the given liquid. If the body is slightly pushed into the liquid, then the body,

archimedes' principle fluid pressure properties of matter physics

  1. sinks in the liquid and settles at the bottom.

  2. come back to its position after some time.

  3. keeps oscillating in vertical direction.

  4. it jumps into the air and falls on the liquid.

Show answer
Correct Option: B
Explanation:

Before pushing body was in the position of equilibrium so if we disturbs the eqm than with the passage of time it would come back to its eqm position .

so option (B) is correct

Apparent loss of weight of a body when immersed in a liquid can be explained on the basis of 

archimedes' principle fluid pressure properties of matter physics

  1. molecular theory.

  2. electron theory.

  3. Archimedes' principle.

  4. Bernoulli's principle.

Show answer
Correct Option: C
Explanation:

Archimedes principle states that  loss in weight of a partially or fully immersed body in a fluid is equal to the weight of the fluid displaced .

so , option (C) is correct

A ball floats on the surface of water in a container exposed to the atmosphere. Will the ball remain immersed at its former depth or will it sink or rise if the container is covered and the air is removed:

archimedes' principle fluid pressure properties of matter physics

  1. The ball sinks

  2. The ball rises

  3. The ball remains immersed at its former depth

  4. It oscillates

Show answer
Correct Option: A

A piece of ice is floating on water in a container. What will happen to the surface of the water when whole ice piece melts

archimedes' principle fluid pressure properties of matter physics

  1. Will go up

  2. Will not change

  3. Will go down

  4. Noe of these

Show answer
Correct Option: B
Explanation:
The water level eill not change. As the mass of ice before and after melting will remain same. When the ice was floating, the volume of water displaced has the mass equal to that of ice. After melting, that mass of ice has been converted into water. 
Thus there is no net change in level.