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2 years ago

12

Một vật chuyển động từ A đến B cách nhau 90m . Trong nữa đoạn đường đầu vật đi với vận tốc v2 =5m/s , giữa đoạn đường còn lại vậ

t chuyển động với vận tốc v2=3m/s. Sau bao lâu vật đến B

1 answer:

Rainbow [258]2 years ago

6 0

お前なに言ってんのか全然わかんない...

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The cockroach Periplaneta americana can detect a static electric field of magnitude 8.50 kN/C using their long antennae. If the

erica [24]

Answer:

0.235 nC

Explanation:

Given:

$E$ = the magnitude of electric field = $8.50\ kN/C =8.50\times 10^{3}\ N/C$

$F$ = the magnitude of electric force on each antenna = $2.00\ \mu N =2.00\times 10^{-6}\ N$

$q$ = The magnitude of charge on each antenna

Since the electric field is the electric force applied on a charged body of unit charge.

$\therefore E = \dfrac{F}{q}\\\Rightarrow q =\dfrac{F}{E}\\\Rightarrow q =\dfrac{2.00\times 10^{-6}\ N}{8.50\times 10^{3}\ N/C}\\\Rightarrow q =0.235\times 10^{-9}\ C\\\Rightarrow q =0.235\ nC$

Hence, the value of q is 0.235 nC.

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3 years ago

According to the diagram of the electromagnetic spectrum shown, what would best represent the

iren2701 [21]

The best represent the size of visible light will be C. Protozoa

The electromagnetic spectrum, gives the overall distribution of electromagnetic radiation by the frequency or wavelength. All EM waves travel at the speed of light in a vacuum, but over a wide range of frequencies, wavelengths, and photon energies.

Visible light wavelengths cover the range of approximately 0.4 to 0.7 μm. electromagnetic spectrum that the human eye can see is the Visible light. Visible light is a form of electromagnetic (EM) radiation, along with radio waves, infrared, ultraviolet, X-rays, and microwaves. the wavelengths that are visible to most human eyes is generally known as Visible light

the best represent the size of visible light is Protozoa, According to the diagram of the electromagnetic spectrum shown,

Learn more about electromagnetic spectrum here brainly.com/question/25847009

#SPJ9

6 0

1 year ago

How many significant figures are in 50.5?

Art [367]

3 as a single number is considered a sf

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3 years ago

Whenever possible, these types of power plants should be built because they generate virtually no pollution. (2 points)

geniusboy [140]

Wind farms, solar collectors, and nuclear power plants generate no pollution.

But wind farms make noise, wind and solar are both hazardous to birds, and there's no known means of disposing of nuclear plant waste that's completely safe.

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3 years ago

A charge is divided q1 and (q-q1)what will be the ratio of q/q1 so that force between the two parts placed at a given distance i

Arturiano [62]

Answer:

$q / q_{1} = 2$ , assuming that $q_{1}$ and $(q - q_{1})$ are point charges.

Explanation:

Let $k$ denote the coulomb constant. Let $r$ denote the distance between the two point charges. In this question, neither $k$ and $r$ depend on the value of $q_{1}$ .

By Coulomb's Law, the magnitude of electrostatic force between $q_{1}$ and $(q - q_{1})$ would be:

$\begin{aligned}F &= \frac{k\, q_{1}\, (q - q_{1})}{r^{2}} \\ &= \frac{k}{r^{2}}\, (q\, q_{1} - {q_{1}}^{2})\end{aligned}$ .

Find the first and second derivative of $F$ with respect to $q_{1}$ . (Note that $0 < q_{1} < q$ .)

First derivative:

$\begin{aligned}\frac{d}{d q_{1}}[F] &= \frac{d}{d q_{1}} \left[\frac{k}{r^{2}}\, (q\, q_{1} - {q_{1}}^{2})\right] \\ &= \frac{k}{r^{2}}\, \left[\frac{d}{d q_{1}} [q\, q_{1}] - \frac{d}{d q_{1}}[{q_{1}}^{2}]\right]\\ &= \frac{k}{r^{2}}\, (q - 2\, q_{1})\end{aligned}$ .

Second derivative:

$\begin{aligned}\frac{d^{2}}{{d q_{1}}^{2}}[F] &= \frac{d}{d q_{1}} \left[\frac{k}{r^{2}}\, (q - 2\, q_{1})\right] \\ &= \frac{(-2)\, k}{r^{2}}\end{aligned}$ .

The value of the coulomb constant $k$ is greater than $0$ . Thus, the value of the second derivative of $F$ with respect to $q_{1}$ would be negative for all real $r$ . $F\!$ would be convex over all $q_{1}$ .

By the convexity of $\! F$ with respect to $\! q_{1} \!$ , there would be a unique $q_{1}$ that globally maximizes $F$ . The first derivative of $F\!$ with respect to $q_{1}\!$ should be $0$ for that particular $\! q_{1}$ . In other words:

$\displaystyle \frac{k}{r^{2}}\, (q - 2\, q_{1}) = 0$ <em>.</em>

$2\, q_{1} = q$ .

$q_{1} = q / 2$ .

In other words, the force between the two point charges would be maximized when the charge is evenly split:

$\begin{aligned} \frac{q}{q_{1}} &= \frac{q}{q / 2} = 2\end{aligned}$ .

3 0

3 years ago