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Nastasia [14]
3 years ago
13

When a garden hose with an output diameter of 20 mm is directed straight upward, the stream of water rises to a height of 0.13m

.
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?
Ignore drag and assume that the smaller opening you create with your thumb is circular.
Physics
1 answer:
fomenos3 years ago
8 0

Answer:

y₂= 2.08  m

Explanation:

This problem should use the fluid continuity equation and kinematics to find the speeds.

Let's start by finding the initial velocity (vo) so that the water reaches the height (y1 = 0.13 m), with kinematics

    vf² = v₀² - 2 g y₁

    0 = v₀² - 2 g y₁

    v₀ = √ 2g y₁

    v₀ = √ (2 9.8 0.13)

    v₀ = 1,596 m / s

Now let's use the fluid continuity equation

   A₁ v₁ = A₂ v₂

The initial speed the speed with the largest diameter

   v₁ = v₀ = 1,596 m / s

Let's look for the areas

   r = d / 2

   r₁ = 20/2 = 10 mm = 10 10⁻³m

   r₂ = 10/2 = 5 mm = 5 10⁻³ m

   A = pi R²

   A₁ = π (10 10⁻³)²

   A₁ = π 10⁻⁴  m²

   A₂ = π5 10⁻³)²

   A₂ = π 25 10⁻⁶ m²2

We cleared the exit speed (v2) by reducing the diameter (d2)

    v₂ = v₁ A₁ / A₂

    v₂ = 1,596 π 10⁻⁴ / π 25 10⁻⁶

    v₂ = 6.38 m / s

Now we find the height for this speed again

   vf² = v₂² - 2g y₂

   0 = v₂² - 2 g y₂

  y₂ = v₂² / 2g

 y₂= 6.38² / (2  9.8)

 y₂= 2.08  m

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a circuit element having terminals a and b has vab = 10v and iba = 2a over a period of 20s, how much charge moves throught the e
PIT_PIT [208]

Answer: charge Q = 40Coulombs

Explanation: The current in a circuit is the quantity of charge that flows through it per second.

Here the 2amp current is same as the amount of charge in coulomb that flows through the terminal in ONE second.

So, if 2 coulomb of charge flows in 1sec then in 20 secs we will have

Q(charge) = 2*20 = 40 coulombs

6 0
3 years ago
The electric potential in a region of uniform electric field is -1600 V at x = -1.30 m and + 2000 V at x =+ 1.80 m . What is Ex?
Inga [223]

Answer:

-1161.29 V/m

Explanation:

The x component of electric field will be given by

E_x= -\frac {\triangle V}{\triangle x}

Here \triangle V is the change in voltage while triangle x is the change in x

E_x= -\frac {+2000 V--1600V}{\triangle 1.8--1.3}=-\frac {3600}{3.1}=-1161.29 V/m

6 0
3 years ago
A baseball is hit almost straight up into the air with a speed of 26 m/s . Estimate how high it goes.
kipiarov [429]

Answer:

The maximum height of the ball is 34.5 m.

The ball is 5.31 s in the air.

Explanation:

Hi there!

The equations for the height and velocity of the baseball that is hit straight up are as follows:

y = y0 + v0 · t + 1/2 · g · t²

v = v0 + g · t

Where:

y = height of the baseball at time t.

y0 = initial height.

v0 = initial velocity.

t = time.

g =  acceleration due to gravity (-9.8 m/s² considering the upward direction as positive).

v = velocity at time t.

If we place the origin of the frame of reference at the place where the baseball is hit, then, y0 = 0.

To calculate how high it goes, we have to obtain the time at which the ball is at maximum height. At that point, the velocity is 0. Then using the equation of velocity:

v = v0 + g · t

0 = 26 m/s - 9.8 m/s² · t

-26 m/s / -9.8 m/s² = t

t = 2.65 s

The height at that time will be the maximum height:

y = y0 + v0 · t + 1/2 · g · t²        (y0 = 0)

y = 26 m/s · 2.65 s - 1/2 · 9.8 m/s² · (2.65 s)²

y = 34.5 m

The maximum height of the ball is 34.5 m

If it takes the ball 2.65 s to reach the maximum height it will take another 2.65 s to return to the initial position. Then, the time it will be in the air is (2.65 s + 2.65 s) 5.30 s. However, let´s calculate the time it takes the ball to reach the initial position using the equation for height.

At the initial position y = 0. Then:

y = y0 + v0 · t + 1/2 · g · t²        (y0 = 0)

0 = 26 m/s · t - 1/2 · 9.8 m/s² · t²

0 = t (26 m/s - 1/2 · 9.8 m/s² · t)      (t = 0 when the ball is hit)

0 = 26 m/s - 1/2 · 9.8 m/s² · t

-26 / -4.9 m/s² = t

t = 5.31 s     ( the difference with the 5.30 s obtained above is due to rounding the time to 2.65 s).

The ball is 5.31 s in the air.

Have a nice day!

3 0
3 years ago
A football is kicked with a velocity of 31 meters per second at an angle of 41 degrees what is the balls acceleration in the ver
IgorC [24]

Answer:

The vertical component of the acceleration is equal to the acceleration due to gravity g.

Explanation:

Given data,

The initial velocity of the football, u = 31 m/s

The angle of direction of the football with the horizontal, Ф = 41°

In free fall, the vertical component of acceleration always remains the same.

Since the ball is clicked in a particular direction that has a vertical component,  then the vertical component of the velocity of the ball is always acted upon by the gravitational force of the earth.

The horizontal component of the velocity of the projectile remains the same because the gravitational force doesn't act in the horizontal direction.

Since the only force is the gravitational force acts on the projectile, the vertical component of the acceleration is equal to the acceleration due to gravity g.

8 0
3 years ago
Read 2 more answers
A boulder of mass 2000. kg breaks loose of a mountainside and plunges 200. m straight down into a lake at a temperature of 5.00◦
natka813 [3]

Answer:

DS = 13865.7[J/K]

Explanation:

We can calculate the energy of the rock, like the potential energy relative to the lake level. Which can be calculated by means of the following expression of the potential energy:

E_{p}=m*g*h\\\\where:\\m = mass = 2000[kg]\\h = elevation = 200 [m]\\g = gravity = 9.81[m/s^2]

Therefore:

E_{p}=2000*9.81*200\\E_{p}=3924000 [J]\\

This energy is transformed into thermal energy.

we shall remember that isothermal heat transfer processes are internally reversible, so the entropy change of a system during one of these processes can be determined, by the following expression.

DS=\frac{Q}{T}\\ where:\\DS = entropy change [J/K]\\Q = Heat transfer [J]\\T = temperature [K]

T = 5 + 278 = 283[K]

DS = 3924000 / 283

DS = 13865.7[J/K]

5 0
4 years ago
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