Tag: physics

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Questions Related to physics

Multiple choice physics upthrust in fluids, archimedes' principle and floatation applications of floatation principle of floatation and its applications when do objects float on water?

Give reasons as to why bodies like cork or wood float in water.

  1. They are denser than water

  2. They are less dense than water

  3. They have the same density as that of water

  4. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Density of cork or wood are less than that of water hence they float in water

Multiple choice physics upthrust in fluids, archimedes' principle and floatation applications of floatation principle of floatation and its applications when do objects float on water?

Give reasons as to why bodies like stones and metals sink in water.

  1. They have higher density compared to water

  2. <span>They have lesser density compared to water</span>

  3. <span>They have the same density as that of water</span>

  4. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Bodies like stones ans metals sink in water as these substances have density more than that of water

Multiple choice physics upthrust in fluids, archimedes' principle and floatation applications of floatation principle of floatation and its applications when do objects float on water?

A hot air balloon rises because it is filled with a gas :

  1. denser than air

  2. less dense than air

  3. as dense as air

  4. the given statement is wrong
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

More denser objects stays at the bottom.

Since, the hot air balloon rises because it is filled with a gas which is less dense than the air .So, the air has the tendency to move down and the balloon has the tendency to move in the upward direction.

Multiple choice physics upthrust in fluids, archimedes' principle and floatation applications of floatation principle of floatation and its applications when do objects float on water?

What happens when an object having density less than that of water is immersed in it?

  1. It sinks

  2. It floats

  3. Unsure

  4. May sink or float
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

the buoyant force depends on the density of liquid. When the density of the object is less than that of the liquid, it floats on the liquid because the upthrust or buoyant force of water is more than the gravity acting on the object.

Multiple choice physics upthrust in fluids, archimedes' principle and floatation applications of floatation principle of floatation and its applications when do objects float on water?

If the weight of the body immersed in the liquid is equal to the force of buoyancy acting on it, then the body will

  1. Float above the liquid surface

  2. Float just inside the liquid surface.

  3. Sink

  4. None
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

If the weight of the body immersed in the liquid is equal to the force of buoyancy acting on it, then the body will float just inside the liquid surface.

Multiple choice physics upthrust in fluids, archimedes' principle and floatation applications of floatation principle of floatation and its applications when do objects float on water?

A piece of ice is floating in a jar containing water. When ice melts, the temperature of water falls from $4^0C$ to $1^0C$. The level of water :

  1. rises

  2. falls

  3. remains unchanged

  4. changes erratically
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Remains unchanged because there is no change in mass.

The correct option is C.

Multiple choice physics upthrust in fluids, archimedes' principle and floatation applications of floatation principle of floatation and its applications when do objects float on water?

A steel wire of length 1 m and cross-sectional area $1.5 mm^2$ is hung from. rigid support, with a stone of volume 2000 cm^3 hanging from the other end. Find the decrease in the length of the wire, when the stone is completely immersed in water. (Ysteel = $210^11 Nm^-2$, $\rho$ water = $103 kgm^-3$)

  1. 0.06533 mm

  2. 0.02533 mm

  3. 0.04533 mm

  4. 0.011533 mm
Reveal answer Fill a bubble to check yourself
C Correct answer
Multiple choice physics upthrust in fluids, archimedes' principle and floatation applications of floatation principle of floatation and its applications when do objects float on water?

A person of mass $m$ is standing on one end of a plank of mass $M$ and length $L$ and floating in water. The person moves from one end to another and stops. The displacement of the plank is :

  1. $\dfrac {Lm}{(m+M)}$

  2. $Lm(M+m)$

  3. $\dfrac {(m+M)}{Lm}$

  4. $\dfrac {LM}{(m+M)}$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Since there is no external horizontal force, the center of mass of the system remains stationary. m*x + M*X = 0, where x and X are displacements. The person moves distance L relative to the plank, so x_person = L - X_plank. Solving m(L - X) + MX = 0 gives X = -mL / (m+M). The magnitude is mL / (m+M).