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When a garden hose with an output diameter of 20 mm is directed straight upward, the stream of water rises to a height of 0.16 m . You then use your thumb to partially cover the output opening so that its diameter is reduced to 10 mm. How high does the water rise now?

Respuesta :

Answer:

the water rise is 2.56 m

Explanation:

Given data

diameter = 20 mm

height = 0.16 m

diameter is reduced = 10 mm

to find out

How high does the water rise

solution

we will apply here Bernoulis equation that is

Area  × velocity that is constant at starting point opening

so that A1V1 = A2V2        .............1  

and we know v = √(2gh)   ...........2         from KE= PE,  ∵ 1/2mv² = mgh

and we know

area here = πd²/4

so from equation 1

A1V1 = A2V2

πd1²/4 × √(2gh1) = πd2²/4 × √(2gh2)

(d1/d2 )² √(2gh1)  =  √(2gh2)

so here d1 = 10 mm  and  d2 = 20 mm and h1 = 0.16 m put all value

400 / 100  √(2g0.16)  =  √(2gh2)

4√(2g0.16)  =  √(2gh2)

16× 2g × 0.16 = 2g × h2

h2 = 16 × 0.16

h2 = 2.56 m

so the water rise is 2.56 m

The new height risen by the water is 2.56 m.

Continuity equation

Continuity equation is used to described the relationship between the flow rate from one point to another in a conduit.

Q₁ = Q₂

A₁V₁ = A₂V₂

The velocity of water in each point is determined by applying the principle of conservation of mechanical energy.

K.E = P.E

¹/₂mv² = mgh

v = √2gh

[tex]A_1 \sqrt{2gh_1} = A_2\sqrt{2gh_2} \\\\\frac{\pi d_1^2 }{4} \sqrt{2gh_1} = \frac{\pi d_2^2}{4} \sqrt{2gh_2} \\\\d_1^2\sqrt{2gh_1 } = d_2^2\sqrt{2gh_2} \\\\\sqrt{2gh_2} = \frac{d_1^2\sqrt{2gh_1 }}{d_2^2} \\\\2gh_2 = \frac{d_1^4\times 2gh_1}{d_2^4} \\\\h_2 = \frac{d_1^4h_1}{d_2^4} \\\\h_2 = \frac{(20\times 10^{-3})^4}{(10\times 10^{-3})^4} \times 0.16\\\\h_2 = 2^4 \times 0.16\\\\h_2 = 2.56 \ m[/tex]

Thus, the new height risen by the water is 2.56 m.

Learn more about continuity equation here: https://brainly.com/question/14619396

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