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3 years ago

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An object accelerates at 20 m/s2. By how much does the speed change in one second?

1 answer:

iren [92.7K]3 years ago

7 0

Explanation:

a= v/t

v= at

= 20m/s2 × 1sec

= 20m/s

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Holes are being steadily injected into a region of n-type silicon (connected to other devices, the details of which are not impo

Tems11 [23]

Complete Question

The complete question is shown on the first uploaded image

Answer:

The value is $J_n = -0.864 \ A/cm^2$

Explanation:

Generally for an n-type semiconductor the current density is mathematically represented as

$J_n = -q * d_p * \frac{d p_{n_o}}{d_w}$

Here $p_{n_o}$ is mathematically represented as

$p_{n_o} = \frac{n_i^2}{n_d}$

=> $p_{n_o} = \frac{(1.5*10^{10})^2}{10^{16}}$

=> $p_{n_o} = 2.25 *10^{4} \ cm^{-3}$

So

$d p_{n_o} = P_n0 - p_{n_o}$

From the diagram $P_n0 = 10^8 * p_{n_o}$

=> $P_n0 = 10^8 * (2.25 *10^{4} )$

So

$d p_{n_o} = 10^8 * (2.25 *10^{4} ) - 2.25 *10^{4}$

$d p_{n_o} = 2.25 *10^{12} cm^{-3}$

So from $J_n = -q * d_p * \frac{d p_{n_o}}{d_w}$

substitute

$1.60 *10^{-19} \ C$ for q and $w_2 =50 nm = 50*10^{-9} m = 5*10^{-6} cm$

and from the diagram $w_1 =0 \ cm$

So

$J_n = -1.60 *10^{-19} *12 * \frac{2.25 *10^{12} }{ 5*10^{-6} - 0 }$

$J_n = -0.864 \ A/cm^2$

6 0

3 years ago

A 0.35-kgkg cord is stretched between two supports, 7.4 mm apart. When one support is struck by a hammer, a transverse wave trav

Agata [3.3K]

Answer:

The tension in the string is $T = 1.49*10^{-6}N$ .

Explanation:

For a string with tension $T$ and linear density $\mu_d$ carrying a transverse wave at speed $v$ it is true that

$v = \sqrt{\dfrac{T}{\mu_d} }$

solving for $T$ we get:

$T = \dfrac{v^2}{\mu_d}.$

Now, the transverse wave covers the distance of 7.4mm in 0.88s, which means it's speed is

$v =\dfrac{7.4*10^{-3}m}{0.88s} \\\\v = 8.4*10^{-3}s$

And it's linear density (mass per unit length) is

$\mu_d = \dfrac{0.35kg}{7.4*10^{-3}m} \\\\\mu_d = 47.3kg/m$

Therefore, the tension in the cord is

$T = \dfrac{(8.4*10^{-3}m/s^2)^2}{47.3kg/m}.$

$\boxed{T = 1.5*10^{-6}N}$

or in micro newtons

$T =1.5\mu N$

4 0

3 years ago

IF a car trip 400 km in four hours what is the rate of speed that a car is traveling?

Andreas93 [3]

Speed = Distance/ Time

Speed = 400 / 4

Speed = 100 km/hr.

100 km per hour.

8 0

3 years ago

Imagine you derive the following expression by analyzing the physics of a particular system: v2=v20+2ax. The problem requires so

lisabon 2012 [21]

As per kinematics equation we are given that

$v^2 = v_o^2 + 2ax$

now we are given that

a = 2.55 m/s^2

$v_0 = 21.8 m/s$

$v = 0$

now we need to find x

from above equation we have

$0^2 = 21.8^2 + 2(2.55)x$

$0 = 475.24 + 5.1 x$

$x = 93.2 m$

so it will cover a distance of 93.2 m

7 0

3 years ago

Read 2 more answers

Electromagnetic radiation behaves both as particles (called photons) and as waves. Wavelength (λ) and frequency (ν) are related

inessss [21]

<h2>Answer: 136.363 m</h2>

Explanation:

We can find the wavelength of the radiation produced by the microwave oven by using the following given equation:

$c=\lambda.\nu$ (1)

Clearing $\lambda$ :

$\lambda=\frac{c}{\nu}$ (2)

Knowing $\nu=2.20 GHz=2.20(10)^{6}Hz=2.20(10)^{6}s^{-1}$

$\lambda=\frac{3(10)^{8}m/s}{2.20(10)^{6}s^{-1}}$ (3)

$\lambda=136.363m$ This is the wavelength of the radiation produced by the microwave

8 0

3 years ago