Tag: option b: engineering physics

Questions Related to option b: engineering physics

A gas is enclosed in a rectangular vessel. $20 \times 10^23$ molecules of the gas strike a well of the vessel normally per second, with a velocity of 250m/s and rebound with the same speed in the opposite direction. What is the force exerted by the gas on the wall if the mass of each molecule is $5 \times 10^-23$ g ? 

physics option b: engineering physics buoyancy floatation fluid pressure

  1. 50 N

  2. 40 N

  3. 75 N

  4. 25 N

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Correct Option: A

A pump is required to lift 1000 kg of water per minute from a well 20 m deep and eject it at a rate of 20 $ms^-1$. What (horsepower engine is required for the purpose of lifting water)?

physics option b: engineering physics buoyancy floatation fluid pressure

  1. $4.46 HP$

  2. $4.36 HP$

  3. $3.96 HP$

  4. $8.85 HP$

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Correct Option: A

The branch of physics which deals with the study of fluids at rest is called :

physics option b: engineering physics buoyancy floatation fluid pressure

  1. statistics

  2. hydrostatics

  3. hydrodynamics

  4. thermometry

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Correct Option: B
Explanation:

The branch of physics which deals with the study of fluids at rest is called hydrostatics.

Hydro stands for liquids and statics is for the fluid at rest.

KE per unit volume is E. The pressure exerted by the gas is given by:

physics option b: engineering physics buoyancy floatation fluid pressure

  1. $\displaystyle \frac {E}{3}$

  2. $\displaystyle \frac {2E}{3}$

  3. $\displaystyle \frac {3E}{2}$

  4. $\displaystyle \frac {E}{2}$

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Correct Option: B
Explanation:

Pressure exerted by gas is given by $P=\dfrac{1}{3}\rho v^2$

where $v$ is the velocity of gas particles, $\rho $ is the density of gas.
Kinetic energy per unit volume$=E=\dfrac{\dfrac{1}{2}mv^2}{V}=\dfrac{1}{2}\rho v^2$
Thus $P=\dfrac{2}{3}(\dfrac{1}{2}\rho v^2)=\dfrac{2E}{3}$

Water is floating smoothly through a closed-pipe system. At one point $A$, the speed of the water is $3.0\ m$ while at another point $B$, $1.0\ m$ higher, the speed is $4.0\ m/s$. The pressure at $A$ is $20\ kPa$ when the flowing $18\ kPa$ when the water flow stop. Then

physics option b: engineering physics buoyancy floatation fluid pressure

  1. the pressure at $B$ when water is flowing is $6.5\ kPa$

  2. the pressure at $B$ when water is flowing is $8.0\ kPa$

  3. the pressure at $B$ when water is flowing is $10\ kPa$

  4. None of these

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Correct Option: A,C

A cylindrical container is filled with water upto the brim. If the pressure exerted by the water at the bottom of the container is 1000 Pa the height of the container is ..........cm.(take $g = 10 m s^{-2}$)

physics option b: engineering physics buoyancy floatation fluid pressure

  1. 10

  2. 100

  3. 1

  4. 20

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Correct Option: A
Explanation:

pressure inside a fluid = $\rho gh$ , in this case $\rho$ = 1000 kg $  m^{3}$

so , 
1000 =  (1000)(10) (h)
hence h = 0.1 m = 10 cm
hence option (A) is correct

Two vessels have different base area. They are filled with water to the same height. If the amount of water in one be $4$ times that in the other, then the ratio of pressure on their bottom will be :

physics option b: engineering physics buoyancy floatation fluid pressure

  1. $16:1$

  2. $8:1$

  3. $4:1$

  4. $1:1$

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Correct Option: C

A cylinder at a certain ternperature has a gas at a pressure ot $50cm$ of Hg.Then it is divided into three equal parts so that the gas in the central part is completely transferred to either equally. Find the pressure of the gas in each portion.

physics option b: engineering physics buoyancy floatation fluid pressure

  1. $10cm$

  2. $20cm$

  3. $75cm$

  4. $100cm$

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Correct Option: B

The length of vacuum above mercury column in a barometer is $10cm/cc$ of air from outside where the pressure is $76cm$ of Hg is passed into the barometer tube. The area of cross section of the tube is $1{ cm }^{ 2 }$.The height of the mercury column then will be

physics option b: engineering physics buoyancy floatation fluid pressure

  1. $71cm$

  2. $72cm$

  3. $73cm$

  4. $74cm$

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Correct Option: C

a circular tank has a hole of 1 cm^2 in its bottom. if the watre is allowed to flow into tank from a tube above it at the rate of $70 cm^3/sec$ then the max height upto which water can rise in the tank

physics option b: engineering physics buoyancy floatation fluid pressure

  1. 2.5 cm

  2. 5 cm

  3. 10 cm

  4. 0.25 cm

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Correct Option: C