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3 years ago

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What statement applies to the horizontal rows or periods in the periodic table? A. The properties are all the same. B. The eleme

nts have the same number of electrons. C. The properties change going across each row. D. The elements in each row combine easily.

1 answer:

Sliva [168]3 years ago

7 0

The right answer for the question that is being asked and shown above is that: "C. <span>. The properties change going across each row. " the </span>statement that applies to the horizontal rows or periods in the periodic table is that t<span>he properties change going across each row. </span>

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Just asking how everyone is doing cause of the virus

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Answer:

We are all fiine

Explanation:

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3 years ago

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A 44-cm-diameter water tank is filled with 35 cm of water. A 3.0-mm-diameter spigot at the very bottom of the tank is opened and

cricket20 [7]

Answer:

The frequency $f$ = 521.59 Hz

The rate at which the frequency is changing = 186.9 Hz/s

Explanation:

Given that :

Diameter of the tank = 44 cm

Radius of the tank = $\frac{d}{2}$ = $\frac{44}{2}$ = 22 cm

Diameter of the spigot = 3.0 mm

Radius of the spigot = $\frac{d}{2}$ = $\frac{3.0}{2}$ = 1.5 mm

Diameter of the cylinder = 2.0 cm

Radius of the cylinder = $\frac{d}{2}$ = $\frac{2.0}{2}$ = 1.0 cm

Height of the cylinder = 40 cm = 0.40 m

The height of the water in the tank from the spigot = 35 cm = 0.35 m

Velocity at the top of the tank = 0 m/s

From the question given, we need to consider that the question talks about movement of fluid through an open-closed pipe; as such it obeys Bernoulli's Equation and the constant discharge condition.

The expression for Bernoulli's Equation is as follows:

$P_1+\frac{1}{2}pv_1^2+pgy_1=P_2+\frac{1}{2}pv^2_2+pgy_2$

$pgy_1=\frac{1}{2}pv^2_2 +pgy_2$

$v_2=\sqrt{2g(y_1-y_2)}$

where;

P₁ and P₂ = initial and final pressure.

v₁ and v₂ = initial and final fluid velocity

y₁ and y₂ = initial and final height

p = density

g = acceleration due to gravity

So, from our given parameters; let's replace

v₁ = 0 m/s ; y₁ = 0.35 m ; y₂ = 0 m ; g = 9.8 m/s²

∴ we have:

v₂ = $\sqrt{2*9.8*(0.35-0)}$

v₂ = $\sqrt {6.86}$

v₂ = 2.61916

v₂ ≅ 2.62 m/s

Similarly, using the expression of the continuity for water flowing through the spigot into the cylinder; we have:

v₂A₂ = v₃A₃

v₂r₂² = v₃r₃²

where;

v₂r₂ = velocity of the fluid and radius at the spigot

v₃r₃ = velocity of the fluid and radius at the cylinder

$v_3 = \frac{v_2r_2^2}{v_3^2}$

where;

v₂ = 2.62 m/s

r₂ = 1.5 mm

r₃ = 1.0 cm

we have;

v₃ = $(2.62 m/s)*$ $(\frac{1.5mm^2}{1.0mm^2} )$

v₃ = 0.0589 m/s

∴ velocity of the fluid in the cylinder = 0.0589 m/s

So, in an open-closed system we are dealing with; the frequency can be calculated by using the expression;

$f=\frac{v_s}{4(h-v_3t)}$

where;

$v_s$ = velocity of sound

h = height of the fluid

v₃ = velocity of the fluid in the cylinder

$f=\frac{343}{4(0.40-(0.0589)(0.4)}$

$f= \frac{343}{0.6576}$

$f$ = 521.59 Hz

∴ The frequency $f$ = 521.59 Hz

b)

What are the rate at which the frequency is changing (Hz/s) when the cylinder has been filling for 4.0 s?

The rate at which the frequency is changing is related to the function of time (t) and as such:

$\frac{df}{dt}= \frac{d}{dt}(\frac{v_s}{4}(h-v_3t)^{-1})$

$\frac{df}{dt}= -\frac{v_s}{4}(h-v_3t)^2(-v_3)$

$\frac{df}{dt}= \frac{v_sv_3}{4(h-v_3t)^2}$

where;

$v_s$ (velocity of sound) = 343 m/s

v₃ (velocity of the fluid in the cylinder) = 0.0589 m/s

h (height of the cylinder) = 0.40 m

t (time) = 4.0 s

Substituting our values; we have ;

$\frac{df}{dt}= \frac{343*0.0589}{4(0.4-(0.0589*4.0))^2}$

= 186.873

≅ 186.9 Hz/s

∴ The rate at which the frequency is changing = 186.9 Hz/s when the cylinder has been filling for 4.0 s.

8 0

3 years ago

What is the electrical consumption in KVA of a motor powered by a 3-phase, 60 Hz, 460 VAC supply that continuously draws 17 A

MrRa [10]

Answer:

15.34 kVA

Explanation:

A motor is a device that converts electrical energy into mechanical energy. It takes in electrical energy at the input and produce torque (motion) at the output.

The power consumption for a three phase motor is the product of voltage and current and √3. The √3 is because it is a three phase supply.

Hence Power (P) =√3 × voltage (V) × current (I)

P = √3 × V × I

Given that voltage (V) = 460 V, current (I) = 17 A. Hence:

P = √3 × V × I = √3 × 460 × 17 = 13544.64 VA

But 1000 VA = 1 kVA. Hence:

$P=13544.64\ VA*\frac{1\ kVA}{1000\ VA}=13.54\ kVA$

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3 years ago

Show that the optimal launch angle for a projectile subject to gravity is 45o by carrying out the following steps: 6. Write down

Lorico [155]

Answer:

sin 2θ = 1 θ=45

Explanation:

They ask us to prove that the optimal launch angle is 45º, for this by reviewing the parabolic launch equations we have the scope equation

R = Vo² sin 2θ / g

Where R is the horizontal range, Vo is the initial velocity, g the acceleration of gravity and θ the launch angle. From this equation we see that the sine function is maximum 2θ = 90 since sin 90 = 1 which implies that θ = 45º; This proves that this is the optimum angle to have the maximum range.

We calculate the distance traveled for different angle

R = vo² Sin (2 15) /9.8

R = Vo² 0.051 m

In the table are all values in two ways

Angle (θ) distance R (x)

0 0 0

15 0.051 Vo² 0.5 Vo²/g

30 0.088 vo² 0.866 Vo²/g

45 0.102 Vo² 1 Vo²/g

60 0.088 Vo² 0.866 Vo²/g

75 0.051 vo² 0.5 Vo²/g

90 0 0

See graphic ( R Vs θ) in the attached ¡, it can be done with any program, for example EXCEL

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3 years ago

Explain how birds, bats, insects, airplanes, rockets, and hot air balloons achieve their flight.

Oksi-84 [34.3K]

The birds, bats, insects, airplanes, rockets, and hot air balloons achieve their flight by creating high pressure below the aircraft and low pressure above it

<h3>What are living and non-living things?</h3>

They both consist of fundamentally simple building blocks. They are composed of substances or mass. Atmospheric and molecular building blocks make up the world.

In order to create high pressure below the aircraft and low pressure above it, airplanes employ specially built wings.

The wing receives sufficient airflow past it to counteract the weight and drag of the aircraft by utilizing a device to provide thrust, such as a propeller.

High pressure underneath the aircraft and low pressure above it is produced by specially constructed wings used by airplanes.

The wing receives enough airflow through it by the use of a thrust-generating device, like a propeller, to overcome the weight and drag of the aircraft.

The differences between how living and non-living things fly;

1. Moving both living and non-living objects consumes energy. Flying animals utilize their wings to create both lift and propulsion by moving them in relation to the body.

In contrast to most air vehicles, where the components that generate lift, wings, and thrust engines or propellers are distinct, the wings stay stationary.

Animal aviators like birds as well as natural parachuters like patagial as well as human inventions like aircraft as well as rockets that can power spacecraft and spaceplanes are just a few examples of the many things that can fly.

Hence, birds, bats, insects, airplanes, rockets, and hot air balloons achieve their flight by creating high pressure below the aircraft and low pressure above it

To learn more about living and nonliving things, refer to brainly.com/question/7807759

#SPJ1

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