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3 years ago

Hydroelectric plants use __________ to produce electricity. A. fire B. sunlight C. water D. wind

2 answers:

3 0

"Hydro..." means "water". Hydroelectric plants use the kinetic energy
of falling water to produce electrical energy.

I wouldn't exactly say that they "use water", because after they produce
the electrical energy, there's still just as much water as there was before.

oee [108]3 years ago

3 0

Answer:

Explanation:

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const2013 [10]

Answer:

The Forces of Flight

At any given time, there are four forces acting upon an aircraft.

These forces are lift, weight (or gravity), drag and thrust. Lift is

the key aerodynamic force that keeps objects in the air. It is the

force that opposes weight; thus, lift helps to keep an aircraft in

the air. Weight is the force that works vertically by pulling all

objects, including aircraft, toward the center of the Earth. In order

to fly an aircraft, something (lift) needs to press it in the opposite

direction of gravity. The weight of an object controls how strong

the pressure (lift) will need to be. Lift is that pressure. Drag is a

mechanical force generated by the interaction and contract of a

solid body, such as an airplane, with a fluid (liquid or gas). Finally,

the thrust is the force that is generated by the engines of an

aircraft in order for the aircraft to move forward.

Explanation:

5 0

2 years ago

The frequency of the second harmonic of a certain musical instrument is 100 Hz. What is the fundamental frequency of the instrum

ruslelena [56]

The harmonic frequency of a musical instrument is the minimum frequency at which a string that is fixed at both ends in the instrument may vibrate. The harmonic frequency is known as the first harmonic. Each subsequent harmonic has a frequency equal to:
n*f, where n is the number of the harmonic and f is the harmonic frequency. Therefore, the harmonic frequency may be calculated using:
f = 100 / 2
f = 50 Hz

4 0

3 years ago

A circular loop of wire with a radius of 15.0cm and oriented in the horizontal xy-plane is located in a region of uniform magnet

Drupady [299]

Answer:

See answer

Explanation:

The area of the circular loop is given by:

$A = \pi r^2$

The magnetic flux is given by:

$\phi = \int \vec{B} \cdot d\vec{A}$

$d\vec{A}$ is parallel to $\vec{B}$ and $\vec{B}$ is constant in magnitude and direction therefore:

$\phi = \int \vec{B} \cdot d\vec{A}= \int BdAcos(0)= B\int dA= B*(\pi r^2)= \pi Br^2$

Part A)

initially the flux is $\phi =\pi B r^2$

after the interval $\Delta t= 2.4 [m/s]$

the flux is

$\phi = 0$

now, the EMF is defined as:

$\epsilon =- \frac{d \phi}{dt}$ ,

if we consider $\Delta t= 2.4 [m/s]$ very small then we can re-write it as:

$\epsilon =- \frac{\Delta \phi}{\Delta t}$

$\Delta \phi = 0 - \pi B r^2=-\pi (1.7) (0.15)^2=-0.12$

then:

$\epsilon =- \frac{-0.12}{0.0024} = 50 [V]$

Part B)

When looked down from above, the current flows counter clockwise, according to the right hand rule, if you place your thumb upwards (the direction of the magnetic field) and close your fingers, then the current will flow in the direction of your fingers.

3 0

3 years ago

Provided the amplitude is sufficiently great, the human ear can respond to longitudinal waves over a range of frequencies from a

riadik2000 [5.3K]

Answer:

Check the explanation

Explanation:

The beat frequency is

df = f2 - f1

the wavelength is

lamda1 = (v/f1)

and lamda2 = (v/f2)

where v = 340 m/s,f1 = 25.0 kHz and f2 = 20.0 kHz

8 0

3 years ago

A block with mass 0.5kg is forced against a horizontal spring of negligible mass, compressing the spring a distance of 0.2m. whe

dangina [55]

A boiling pot of water (the water travels in a current throughout the pot), a hot air balloon (hot air rises, making the balloon rise) , and cup of a steaming, hot liquid (hot air rises, creating steam) are all situations where convection occurs.
Read more on Brainly.com - brainly.com/question/1581851#readmore

4 0

3 years ago