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3 years ago

How does hydroelectric energy works?

1 answer:

7 0

Actually, hydroelectric and coal-fired power plants produce electricity in a similar way. In both cases a power source is used to turn a propeller-like piece called a turbine, which then turns a metal shaft in an electric generator,which is the motor that produces electricity. A coal-fired power plant uses steam to turn the turbine blades; whereas a hydroelectric plant uses falling water to turn the turbine. The results are the same. :)

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Speed versus Time

Otrada [13]

A since it’s the only one that makes sense! So A is correct.

8 0

3 years ago

A one bucket is fill up with sand and another is empty .Which bucket can oscilliate more when release from the distance

Sav [38]

Answer:

a one bucket with full of sand because of it's mass which plays role in momentum

6 0

3 years ago

A string trimmer is a tool for cutting grass and weeds; it utilizes a length of nylon "string" that rotates about an axis perpen

Kaylis [27]

Answer:

r = 22.3 cm

Explanation:

given,

angular speed = 45 rev/s

tangential speed = 63 m/s

length of the rotating string

angular velocity =

ω = 2 π N

ω = 2 π x 45

ω = 282.74 rad/s

we know,

v = r ω

$r = \dfrac{v}{\omega}$

$r = \dfrac{63}{282.74}$

$r =0.223\ m$

r = 22.3 cm

3 0

4 years ago

A ray of light traveling in air is incident on the surface of a block of clear ice (of index 1.309) at an angle of 25.5 ◦ with t

sergij07 [2.7K]

Answer: $135.29\º$

The figure attached will be helpful to understand the solution.

Here we see two cases, reflection and refraction of light.

According to the laws of reflection:

1. The incident ray, the reflected ray and the normal are in the same plane.

2. The angle of incidence is equal to the angle of reflection.

*Note the normal is perpendicular to the plane, with a $90\º$ angle with the surface

And this can be visualized in the figure, where the angle ${\theta}_{1}$ with which the incident ray hits the surface is equal to the angle with which this same ray is reflected.

On the other hand we have Refraction, a phenomenon in which the light bends or changes its direction when passing through a medium with a refractive index different from the other medium.

In this context, the Refractive index is a number that describes how fast light propagates through a medium or material.

According to Snell’s Law:

$n_{1}sin(\theta_{1})=n_{2}sin(\theta_{2})$ (1)

Where:

$n_{1}=1$ is the first medium refractive index (the air)

$n_{2}=1.309$ is the second medium refractive index (the ice)

$\theta_{1}=25.5\º$ is the angle of the incident ray

$\theta_{2}$ is the angle of the refracted ray

Now, firstly we have to find $\theta_{2}$ and then, by geometry, find $\alpha$ and $\beta$ which sum the angle between the reflected and the refracted light.