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3 years ago

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Một người tác dụng lên mặt sàn một áp suất 1,7.104N/m2. Diện tích của bàn chân tiếp xúc với mặt sàn là 0,03m2. Trọng lượng của n

gười đó là.

1 answer:

velikii [3]3 years ago

6 0

Answer:

Hi, can you ask it in english only?

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HELP ME PLEASE URGENT WILL MARK AND 5 STARS

Artist 52 [7]

Answer:

option (B) is the correct option.

please thanks me and follow me

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3 years ago

Using Gauss's law, calculate the electric field at a point distance s from a long wire bearing uniform charge density. i need he

11111nata11111 [884]

Answer:

E = 2k $\frac{\lambda}{ r}$

Explanation:

Gauss's law states that the electric flux equals the wax charge between the dielectric permeability.

We must define a Gaussian surface that takes advantage of the symmetry of the problem, let's use a cylinder with the faces perpendicular to the line of charge. Therefore the angle between the cylinder side area has the same direction of the electric field which is radial.

Ф = ∫ E . dA = E ∫ dA = q_{int} /ε₀

tells us that the linear charge density is

λ = q_ {int} /l

q_ {int} = l λ

we substitute

E A = l λ /ε₀

is area of cylinder is

A = 2π r l

we substitute

E = $\frac{ l \ \lambda}{ \epsilon_o \ 2\pi \ r \ l }$

E = $\frac{\lambda}{ 2\pi \epsilon_o \ r}$

the amount

k = 1 / 4πε₀

E = 2k $\frac{\lambda}{ r}$

5 0

3 years ago

Suppose you wanted to be able to see astronauts on the moon. What is the smallest diameter of the objective lens required to res

LenaWriter [7]

Answer:

A:1.94

Explanation:

cause that the only one on there

5 0

3 years ago

A hot air balloon is on the ground, 200 feet from an observer. The pilot decides to ascend at 100 ft/min. How fast is the angle

liq [111]

Answer:

0.0031792338 rad/s

Explanation:

$\theta$ = Angle of elevation

y = Height of balloon

Using trigonometry

$tan\theta=y\dfrac{y}{200}\\\Rightarrow y=200tan\theta$

Differentiating with respect to t we get

$\dfrac{dy}{dt}=\dfrac{d}{dt}200tan\theta\\\Rightarrow \dfrac{dy}{dt}=200sec^2\theta\dfrac{d\theta}{dt}\\\Rightarrow 100=200sec^2\theta\dfrac{d\theta}{dt}\\\Rightarrow \dfrac{d\theta}{dt}=\dfrac{100}{200sec^2\theta}\\\Rightarrow \dfrac{d\theta}{dt}=\dfrac{1}{2}cos^2\theta$

Now, with the base at 200 ft and height at 2500 ft

The hypotenuse is

$h=\sqrt{200^2+2500^2}\\\Rightarrow h=2507.98\ ft$

Now y = 2500 ft

$cos\theta=\dfrac{200}{h}\\\Rightarrow cos\theta=\dfrac{200}{2507.98}=0.07974$

$\dfrac{d\theta}{dt}=\dfrac{1}{2}\times 0.07974^2\\\Rightarrow \dfrac{d\theta}{dt}=0.0031792338\ rad/s$

The angle is changing at 0.0031792338 rad/s

6 0

3 years ago

In Lesson 20, a magnesium strip was used to ignite the thermite reaction. When magnesium is placed in a flame from a small blow

nadezda [96]

Answer:

2 electrons will be needed by unbound oxygen in order to fill its 2nd shell.

Explanation:

The chemical reaction between magnesium and oxygen gives magnesium oxide as a product.The reaction is chemically represented as:

$2Mg(s)+O_2(g)\rightarrow 2MgO(s)$

Magnesium is a metal of group-2 with 2 valence electrons.It has atomic number of 12.

$[Mg]=1s^22s^22p^63s^2$

In order to attain noble gas configuration it will loose two electrons.

$[Mg]^{2+}=1s^22s^22p^6$

$Mg\rightarrow Mg^{2+}+2e^-$ ...[1]

Oxygen is a non metal of group-16 with 6 valence electrons..It has atomic number of 8.

$[O]=1s^22s^22p^4$

In order to attain noble gas configuration it will gain two electrons.

$[O]^{2-}=1s^22s^22p^6$

$O+2e^-\rightarrow O^{2-}$ ..[2]

2 electrons will be needed by unbound oxygen in order to fill its 2nd shell.

6 0

4 years ago