Fluid Flow

A liquid flow through a system of two connected tubes at a rate of 4 liters per minute. It gets out from the end of the second tube at a speed of 7 meters per second. Find the cross-sectional area of the second tube.

• $9.52×10^{-6}\ m^2$

• $9.52×10^{-3}\ m^2$

• $5.71×10^{-4}\ m^2$

• $5.71×10^{-5}\ m^2$

Some liquid flows inside a pipe with a cross-sectional area of 0.02 m². The liquid flows at 13 kg/s and has a density of 1‎ ‎200 kg/m³.Calculate the flow speed through the pipe in meters per second.

• 0.54 m/s

• 0.26 m/s

• 3.85 m/s

• 1.85 m/s

A hose which has a radius of 3 cm is used to fill a water tank. If the total amount of water the hose pours is 15 kg and it takes 18 s to fill the tank, what is the velocity of water coming out of the hose? Take water density to be 1‎ ‎000 kg/m³.

• 0.93 m/s

• 0.42 m/s

• 0.29 m/s

• 1.3 m/s

A large water tank can be filled by two water taps. It takes 26 minutes for the tank to be filled by the first water tap only and 39 minutes to be filled by the second water tap only. If both taps are used to fill the tank together at the same time, how many minutes will it take to fill the tank?

• 6.5 minutes

• 32.5 minutes

• 31.2 minutes

• 15.6 minutes

The diagram shows an incompressible liquid flowing in a large pipe, which branches into two smaller pipes with unequal cross-sectional areas. If  $3v_2=4v_1$   and  $A_1=2A_2=3A_3$  . Where 𝑣 is the flow velocity and  $A$   is the cross-sectional area, find the ratio  $\frac{v_3}{v_2}$  .

•  $\frac{3}{4}$  

•  $\frac{2}{3}$  

•  $\frac{3}{2}$  

•  $\frac{4}{3}$  

If a liquid enters a pipe of diameter d with a velocity v, what will it’s velocity at the exit if the diameter reduces to 0.5d?

• v

• 0.5v

• 2v

• 4v

Two pipes, each of diameter d, converge to form a pipe of diameter D. What should be the relation between d and D such that the flow velocity in the third pipe becomes double of that in each of the two pipes?

• D = d

• D = 2d

• D = 3d

• D = 4d

A thin plate of mass 2.5 g is pushed by a constant force 𝐹=0.50mN, moving at a constant 1.32 cm/s over the surface of a viscous liquid that is 2.5 mm deep, as shown in the diagram. The speeds of the layers of the liquid between the plate and the lowest layer of the liquid are shown in the diagram. The liquid in contact with the top and bottom plates move at the same speed as the plates move. What is the dynamic viscosity of the liquid?

• $5.5×10^{-4}\ Pa⋅s$

• $9.4×10^{-4}\ Pa⋅s$

• $8.5×10^{-4}\ Pa⋅s$

• $3.0×10^{-4}\ Pa⋅s$

The floor of a large room is covered by a layer of a viscous fluid, A. A constant tangential force of 60 N acts on a thin rectangular plate, above the fluid, causing the plate to move with a constant velocity of 0.3 m/s. If fluid A is replaced by another viscous fluid, B, the plate can be pushed with a constant tangential force of 40 N, causing the plate to move with a constant velocity of 0.6 m/s. What is the ratio between the viscosity coefficients,  $\frac{\left(η_{vs}\right)_A}{\left(η_{vs}\right)_B}$  ?

•  $\frac{1}{3}$  

•  $\frac{3}{1}$ 

•  $\frac{3}{4}$  

•  $\frac{4}{3}$  

A tangential force of 20 N is applied to a rectangular slab with a length of 60 cm and a width of 40 cm. The slab moves at 1.2 m/s on a viscous liquid. If the liquid has a thickness of 8.9 mm. Find its coefficient of viscosity.

• $1.62\ kg/m⋅s$

• $0.74\ kg/m⋅s$

• $0.62\ kg/m⋅s$

• $1.34\ kg/m⋅s$