Tag: physics

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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 beaker containing water weighs $100$ g. It is placed on the pan of a balance and a piece of metal  weighing 70 g and having a volume of $10c{m^3}$ is placed inside the water in beaker. The weight of the beaker and the metal would be:

  1. $170g$

  2. $160$g

  3. $100$g

  4. $30g$
Reveal answer Fill a bubble to check yourself
B 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 ball rise with constant velocity, to the surface of a liquid whose density is four times that of the ball. The ratio of the v force to weight of the ball is

  1. 1

  2. 2

  3. 3

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

For a body rising with constant velocity, the forces are balanced: Buoyancy = Weight + Viscous Force. F_b = rho_liquid * V * g = 4 * rho_ball * V * g = 4 * Weight. Therefore, Viscous Force = F_b - Weight = 4W - W = 3W. The ratio of viscous force to weight is 3.

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 balloon has volume of 1000 $m^{3}$ . It is filled with hydrogen ($ \rho $ = 0.09 g/L ) . If the density of air is 1.29 g/L , it can lift a total weight of 

  1. 600 kg

  2. 1200 kg

  3. 300 kg

  4. 1800 kg
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Given,
$V _b=1000m^3$
$\rho _h=0.09g/L$
$\rho _a=1.29g/L$
$g=10m/s^2$
Upthrust force = total downward force
$V _b \rho _a h=mg+\rho _h V _b g$
$1000\times 1.29\times 10=mg+0.09\times 1000\times 10$
$1290=mg+90$
$mg=1200kg-weight$
The correct option is B.
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?

 An ice cube is floating on the surface of water. How will the water level be affected by melting of this ice cube?

  1. Water level will be raised

  2. Water level will go down

  3. Water level will remain the same

  4. Water level will first rise up then it will go down
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Archimedes' principle states that a floating object displaces its own weight in fluid. When ice melts, the mass of the resulting water is equal to the mass of the ice, so the volume of water produced is exactly equal to the volume of water displaced by the ice. Thus, the level remains the same.