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olga nikolaevna [1]

3 years ago

5

What is the decibel level of the noise in a typical classroom?

2 answers:

maks197457 [2]3 years ago

6 0

I think it is 100 dB .I holp it is help.

liraira [26]3 years ago

4 0

What is the decibel level of the noise in a typical classroom

50 db

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A 2.0-mm-long, 1.0-mmmm-diameter wire has a variable resistivity given by rho(x)=(2.5×10−6)[1+(x1.0m)2]Ωmrho(x)=(2.5×10−6)[1+(x1

Tresset [83]

Answer:

1.144 A

Explanation:

given that;

the length of the wire = 2.0 mm

the diameter of the wire = 1.0 mm

the variable resistivity R = $\rho (x) =(2.5*10^{-6})[1+(\frac{x}{1.0 \ m})^2]$

Voltage of the battery = 17.0 v

Now; the resistivity of the variable (dR) can be expressed as = $\frac{\rho dx}{A}$

$dR = \frac{(2.5*10^{-6})[1+(\frac{x}{1.0})^2]}{\frac{\pi}{4}(10^{-3})^2}$

Taking the integral of both sides;we have:

$\int\limits^R_0 dR = \int\limits^2_0 3.185 \ [1+x^2] \ dx$

$R = 3.185 [x + \frac {x^3}{3}}]^2__0$

$R = 3.185 [2 + \frac {2^3}{3}}]$

R = 14.863 Ω

Since V = IR

$I = \frac{V}{R}$

$I = \frac{17}{14.863}$

I = 1.144 A

∴ the current if this wire if it is connected to the terminals of a 17.0V battery = 1.144 A

8 0

3 years ago

What’s the net force of an object being throwing into the air

timurjin [86]

Answer: forces acting on an object being thrown into the air is gravity and possibly air resistance

Explanation:

4 0

3 years ago

A mass of 3.0 kg rests on a smooth surface inclined 34° above the horizontal. It is kept from sliding down the plane by a spring

azamat

Answer:

The spring stretched by x = 13.7 cm

Explanation:

Given data

Mass = 3 kg

k = 120 $\frac{N}{m}$

Angle $\theta$ = 34°

From the free body diagram

Force acting on the box = mg sin $\theta$

⇒ F = 3 × 9.81 × $\sin34$

⇒ F = 16.45 N ------- (1)

Since box is attached with the spring so a spring force also acts on the box.

$F_{sp}$ = k x

$F_{sp}$ = 120 $x$ -------- (2)

The net force acting on the body is given by

$F_{net} = ma$

Since acceleration of the box is zero so

$F_{net} = 0$

$F - F_{sp} = 0$

$F = F_{sp}$

Put the values from equation (1) & (2) we get

16.45 = 120 $x$

x = 0.137 m

x = 13.7 cm

Therefore the spring stretched by x = 13.7 cm

3 0

3 years ago

Which pair of elements is most similar?<br> Na and CI<br> Li and Ne<br> Co and<br> Ne and Ar

UkoKoshka [18]

Answer:

If I remembered correctly the answer would be Ne and Ar(Neon and Argon

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3 years ago

How can meteorologists use the jet stream to predict the weather ?

barxatty [35]

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5 0

3 years ago