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3 years ago

What are conductors, semiconductors, non-conductors, dielectrics?

Physics

1 answer:

elena55 [62]3 years ago

5 0

Conductors are substances that pass an electrical charge.

Semiconductors are substances whose electrical conductivity is lower than that of metals and greater than that of dielectrics.

Electricity nonconductors or insulators - in the terminology of Faraday - dielectrics (see). N. perfect does not exist; they represent only a large resistance to galvanic current and then different bodies in varying degrees (see Galvanic current), so that between poor and good conductors there are many bodies of average conductivity. N. The galvanic current is also the best insulators of static electricity. N. Heat or its bad conductors are at the same time electrical insulators (see Thermal Conductivity).

A dielectric (insulator) is a substance that is poorly conducting or not conducting at all. The concentration of free charge carriers in a dielectric does not exceed 108 cm-3. The main property of the dielectric is the ability to polarize in an external electric field. From the point of view of the band theory of a solid body, a dielectric is a substance with a band gap greater than 3 eV.

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Un bloque de 20kg de masa se desplaza horizontalmente en la dirección de eje X por acción de una fuerza horizontal variable F =

zmey [24]

Answer:

a) El trabajo realizado por esta fuerza mientras el bloque se mueve desde la posición x = + 10 m hasta la posición x = + 20 m es 900 joules.

b) La rapidez del bloque en la posición x = + 20 metros es aproximadamente 5.701 metros por segundo.

Explanation:

a) El trabajo expermentado por el bloque ( $W$ ), medido en joules, es definida por la siguiente ecuación integral:

$W = \int\limits^{x_{max}}_ {x_{min}} F(x) \, dx$ (1)

Donde:

$x_{min}$ , $x_{max}$ - Posiciones mínima y máxima del bloque, medidos en metros.

$F(x)$ - Fuerza horizontal aplicada al bloque, medida en newtons.

Si conocemos que $F(x) = 6\cdot x$ , $x_{min} = 10\,m$ y $x_{max} = 20\,m$ , entonces el trabajo realizado por esta fuerza es:

$W = \int\limits^{20\,m}_{10\,m} {6\cdot x} \, dx$ (2)

$W = 6\int\limits^{20\,m}_{10\,m} x\, dx$

$W = 3\cdot x^{2}\left|\limits_{10\,m}^{20\,m}$

$W = 3\cdot [(20\,m)^{2}-(10\,m)^{2}]$

$W = 900\,J$

El trabajo realizado por esta fuerza mientras el bloque se mueve desde la posición x = + 10 m hasta la posición x = + 20 m es 900 joules.

b) La rapidez final del bloque se determina mediante de Teorema del Trabajo y la Energía, es decir:

$W = K_{f}-K_{o}$ (3)

Donde son $K_{o}$ , $K_{f}$ las energías cinéticas traslacionales inicial y final, medidos en joules.

Al aplicar la definición de energía cinética traslacional, expandimos y simplificamos la ecuación como sigue:

$W = \frac{1}{2}\cdot m \cdot (v_{f}^{2}-v_{o}^{2})$ (4)

Donde:

$m$ - Masa del bloque, medido en kilogramos.

$v_{o}$ , $v_{f}$ - Rapideces inicial y final del bloque, medidos en metros por segundo.

$\frac{2\cdot W}{m} = v_{f}^{2}-v_{o}^{2}$

$v_{f} = \sqrt{\frac{2\cdot W}{m}+v_{o}^{2}}$

Si conocemos que $W = 900\,J$ , $m = 20\,kg$ y $v_{o} = \sqrt{10}\,\frac{m}{s}$ , entonces la rapidez final del bloque es:

$v_{f} = \sqrt{\frac{900\,J}{2\cdot (20\,kg)}+10\,\frac{m^{2}}{s^{2}} }$

$v_{f} \approx 5.701\,\frac{m}{s}$

La rapidez del bloque en la posición x = + 20 metros es aproximadamente 5.701 metros por segundo.

6 0

3 years ago

If we were going to describe the relationship between current, voltage, and power, you could say:

sattari [20]

You cannot have power without voltage.

The equation is: Power = voltage times current.

If either voltage is zero or current is zero, there is no power.

Ohm’s Law: Voltage = Current times resistance is also closely related.

If there is zero resistance, power is also zero

8 0

3 years ago

Figure 3

Ludmilka [50]

Answer:

3.92 N (straight down)

2.36 N (down, parallel to the plane)

Explanation:

The only force acting on the system is apparently that due to gravity. The mass of the system is the sum of the masses of the blocks, so is ...

0.20 kg + 0.20 kg = 0.40 kg

The force due to gravity is given by ...

F = ma = (0.40 kg)(9.8 m/s²) = 3.92 N . . . (straight down)

That force is acting straight down, so is at an angle with respect to the direction the blocks are constrained to move.

The force down the plane is (3.92 N)·sin(37°) ≈ 2.359 N . . . (down the plane)

_____

<em>Comment on the answer</em>

We have given two answers to the question, because in this frictionless system, the force acting normal to the plane of motion is irrelevant to the system dynamics. The question asked for the net force on the system, which is the force due to gravity, so we have given that magnitude also.

6 0

3 years ago

Why are clockwise and counterclockwise referred to as “senses,” rather than directions?

Y_Kistochka [10]

Clockwise and counter-clockwise is considered as a sense rather than a direction because it is only a view point where its movement of direction is always changing. Moreover, it is assumed as a tangential velocity of different points on the same body that is spinning in all directions and do not describe the motion of an object. The term can only be applied to object-observer system and not particularly for a direction.

8 0

3 years ago

Read 2 more answers

As a general rule, friction is greatest ________. as a general rule, friction is greatest ________. in the middle latitudes near

Fudgin [204]

Answer:

near earth's surface.

Explanation:

As a general rule, friction is greatest near earth's surface.

Near the Earth surface the air density is highest among the all the places given in the option. Now, since the density is higher the thickness of air column will be higher as well and hence The friction is greatest near earth's surface.

This the reason why planes and jet are flown well above the earth's surface so as to avoid losses due to friction.

4 0

4 years ago