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2 years ago

13

When Maria rubbed her solid graphite pencil against paper, it easily left a clear streak on the paper. Which model could represe

nt graphite?

1 answer:

lyudmila [28]2 years ago

8 0

Answer:

B

Explanation:

:p

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It's a frightening idea, but what would be the sound intensity level of 100 physics professors talking simultaneously

Svetlanka [38]

The sound intensity level of 100 physics professors talking simultaneously is equal to 72 decibel.

<u>Given the following data:</u>

Sound intensity = 52 dB.

<h3>What is sound intensity?</h3>

Sound intensity can be defined as a measure of the power of a sound wave per unit area. Thus, sound intensity is a quantity that can be used to measure the energy of sound and its unit of measurement is Watts per square meter.

<h3>How to calculate the sound intensity level.</h3>

Mathematically, sound intensity level is given by this formula:

$\beta = 10 log(\frac{I}{I_{ref}} )$

<u>Note:</u> The reference value of sound intensity is equal to $1.0 \times 10^{-12}\;W/m^2$

Thus, the sound intensity for one (1) professor is given by:

$I_1 = 1.0 \times 10^{-12} \times 10^{5.2}\\\\I_1=1.585 \times 10^{-7}\;W/m^2$

For 100 professors, the sound intensity is:

$I_{100} = 1.585 \times 10^{-7} \times 100\\\\I_{100}=1.585 \times 10^{-5}\;W/m^2$

Substituting the parameters into the formula, we have;

$\beta = 10 log(\frac{1.585 \times 10^{-5}}{1.0 \times 10^{-12}})\\\\\beta = 10 log(15.58 \times 10^{6})\\\\\beta = 10 \times 7.2\\\\\beta =72\;dB$

Read more on sound intensity here: brainly.com/question/17062836

<u>Complete Question:</u>

One physics professor talking produces a sound intensity level of 52 dB. It's a frightening idea, but what would be the sound intensity level of 100 physics professors talking simultaneously?

7 0

1 year ago

Ampres law is often written contourintegral B vector (r vector) middot dl vector = mu_0I_enclosed. The integral on the left is

uranmaximum [27]

Answer:

(C) line integral along a closed loop

This integral is evaluated by dividing the path into infinitesimal segments dL, calculating the scalar product B•dL for each segment, and sum these products. The component of B parallel to dL at each point is always used in evaluating this integral.

The line integral is equal to mu_o × I.

Explanation:

4 0

2 years ago

(02.06)plz help me 20 points

Flura [38]

Answer:

the answer is 80 degrees

Explanation:

5 0

2 years ago

A solid block of copper, which is a good conductor, has a cavity in its interior. Within the cavity, insulated from the conducto

Nikolay [14]

Answer:

The charge on the outer surface of the block = -5.00 nC

The charge on the surface of the cavity (on the inner surface of the block) = -3.00 nC

Explanation:

The point charge within the cavity will induce a charge equal in magnitude and opposite in sign on the inside cavities of the copper block.

Charge of the point charge = 3.00 nC

Charge induced on the inner surface of the Copper block's cavity = -3.00 nC

Since the charge on a conductor should usually be neutral, the charge on the inner surface causes a charge equal in magnitude and also opposite in sign on the outer surface of the block; that is, 3.00 nC.

But this block already has an excess charge of -8.00 nC (which resides on the surface because excess charge for conductors reside on the surface of the conductors)

So, net charge on the outer surface of the Copper block = -8.00 + 3.00 = -5.00 nC.

Hope this Helps!!!

4 0

2 years ago

. A water balloon is thrown horizontally at a speed of 2.00 m/s from the roof of a building that is 6.00m above the ground. At t

dedylja [7]

Answer:

Explanation:

Height of building

H = 6m

Horizontal speed of first balloon

U1x = 2m/s

Second ballot is thrown straight downward at a speed of

U2y = 2m/s

Time each gallon hits the ground

Balloon 1.

Using equation of free fall

H = Uoy•t + ½gt²

Uox = 0 since the body does not have vertical component of velocity

6 = ½ × 9.8t²

6 = 4.9t²

t² = 6 / 4.9

t² = 1.224

t = √1.224

t = 1.11 seconds

For second balloon

H = Uoy•t + ½gt²

6 = 2t + ½ × 9.8t²

6 = 2t + 4.9t²

4.9t² + 2t —6 = 0

Using formula method to solve the quadratic equation

Check attachment

From the solution we see that,

t = 0.9211 and t = -1.329

We will discard the negative value of time since time can't be negative here

So the second balloon get to the ground after t ≈ 0.92 seconds

Conclusion

The water ballon that was thrown straight down at 2.00 m/s hits the ground first by 1.11 s - 0.92s = 0.19 s.

4 0

2 years ago

Read 2 more answers