Couple of pretty simple liquid q's

In summary, the relationship between the velocity of a liquid being projected vertically and the height it goes can be determined using Bernoulli's equation of continuity for incompressible fluids. In the given problem of a cylindrical tank with a plug removed, the initial speed of the water can be calculated using this equation and then plugged into the equation for motion in a gravitational field to find the final speed at contact with the ground. The correct values for Y1 and Y2 in the equation are 9 and 3, respectively.
  • #1
Jacob87411
171
1
1) First ones just I am curious about what's the relationship between the velocity of a liquid being projected, like out of a hose, vertically and the height it goes.

2) An actual problem: A cylindrical tank .9 m in radius rests atop a platform 6 m high. Initially the tank is filled with water to a depth of h=3m. A plug whose area is 6.3 cm^2 is removed from an orifice in the side of the tank at the bottom. What is the speed of the stream as it strikes the ground.

Will the water have an initially speed when it comes out? Obviously gravity is what is going to accelerate it down at 9.8 m/s, I thought that it would just be the acceleration multiplied by the time because it wouldn't have an initial speed, it was just coming out. This seems to simple and doesn't use the informatyion they gave me so guessing its not the answer
 
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  • #2
Jacob87411 said:
1) First ones just I am curious about what's the relationship between the velocity of a liquid being projected, like out of a hose, vertically and the height it goes.

2) An actual problem: A cylindrical tank .9 m in radius rests atop a platform 6 m high. Initially the tank is filled with water to a depth of h=3m. A plug whose area is 6.3 cm^2 is removed from an orifice in the side of the tank at the bottom. What is the speed of the stream as it strikes the ground.

Will the water have an initially speed when it comes out? Obviously gravity is what is going to accelerate it down at 9.8 m/s, I thought that it would just be the acceleration multiplied by the time because it wouldn't have an initial speed, it was just coming out. This seems to simple and doesn't use the informatyion they gave me so guessing its not the answer

It isn't simple.It's not too difficult,either...Well,...to me,that is...
Calculate the speed at which the particles (molecules if u prefer) at the surface of the water inside the tank begin to fall,once u've opened the plug.Use Bernoulli's equation of continuity for incompressible fluids (the one that states that the flow is conservative),to find at what speed the particles of water exit the tank through the hole.
That would be your initial speed of the water that comes out of the tank.Plug it in the equation for motion in the gravitational field to find the final speed (the speed at the contact with the ground).

Daniel.
 
  • #3
P1 + 1/2PV^2 + PGY1 = P2 + 1/2PV2^2 + PGY2

(I know the P's in 1/2PV^2 are rho for density, new here with the greek letters)

P1 and P2 both 1 atm?
Y1 = The top of the barrel so 3m since its filled up 3m?
Y2 = 0?

If that is the correct way I should be all set
 
  • #4
Or should Y1 be 9 and Y2 be 3 since the barrel is 6m above the ground
 

Related to Couple of pretty simple liquid q's

What is a "couple of pretty simple liquid q's"?

A "couple of pretty simple liquid q's" refers to a few basic questions related to the properties and behavior of liquids, such as their density, viscosity, and surface tension.

What are the most important properties of liquids?

The most important properties of liquids include density, viscosity, surface tension, and boiling point. These properties determine how liquids behave and interact with other substances.

How does density affect the behavior of liquids?

Density is a measure of how tightly packed the molecules in a liquid are. It affects the buoyancy of objects in a liquid, as well as the rate at which liquids mix and flow.

What is surface tension and why is it important for liquids?

Surface tension is the force that causes the surface of a liquid to behave like a thin film, allowing it to support small objects and form droplets. It is important for many natural processes, such as the movement of water through plants and the formation of raindrops.

How does temperature affect the properties of liquids?

Temperature plays a significant role in the properties of liquids. As temperature increases, the molecules in a liquid gain energy and move more quickly, which can affect their density, viscosity, and surface tension. Additionally, temperature can cause a liquid to change states, such as from a liquid to a gas (boiling) or from a liquid to a solid (freezing).

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