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3 years ago

Which of the following statements best explains how heat flows by convection?

Physics

2 answers:

AveGali [126]3 years ago

6 0

It is D for sure!!!!

adell [148]3 years ago

5 0

The answer should be C

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Which factors will increase the speed of a sound wave in the air?

Dafna11 [192]

A higher temperature, stiffer materials, and less dense materials increase the speed of sound.

7 0

3 years ago

3. A certain wire, 3 m long, stretches by 1.2 mm when under tension of 200 N. By how much does

nikitadnepr [17]

Answer:

The extension of the second wire is $e_2 = 0.0024 \ m = 2.4 mm$

Explanation:

From the question we are told that

The length of the wire is $L = 3 \ m$

The elongation of the wire is $e = 1.2mm = \frac{1.2}{1000} = 0.0012 m$

The tension is $F = 200 \ N$

The length of the second wire is $L_2 = 6 \ m$

Generally the Young's modulus(Y) of this material is

$Y = \frac{stress}{strain }$

Where $stress = \frac{F}{A}$

Where A is the area which is evaluated as

$A = \pi r^2$

and $strain = \frac{extention}{length} = \frac{e}{L}$

$Y = \frac{\frac{F}{\pi r^2 } }{ \frac{e}{L} }$

Since the wire are of the same material Young's modulus(Y) is constant

So we have

$\frac{F * L }{r^2 e} = \pi * Y = constant$

$F * L = constant * r^2 e$

Now the ration between the first and the second wire is

$\frac{F_1}{F_2} * \frac{L_1}{L_2} = \frac{r*2_1}{r^2} * \frac{e_1}{e_2}$

Since tension , radius are constant

We have

$\frac{L_1}{L_2} = \frac{e_1}{e_2}$

substituting values

$\frac{3}{6} = \frac{0.0012}{e_2}$

$0.5 e_2 = 0.0012$

$e_2 = \frac{ 0.0012 }{0.5}$

$e_2 = 0.0024 \ m = 2.4 mm$

3 0

3 years ago

Which of the following motions has a straight line?

skad [1K]

The answer would probably be B.

8 0

2 years ago

Angular velocity and linear velocity have the same dimensions. This statement is:

iragen [17]

I think it would be C: Sometimes true and sometimes false. It varies.

Hope this helped, have a great day! :D

5 0

2 years ago

You are parking your vehicle downhill next to a curb. how should you position the wheels

REY [17]

When you stop your car headed downhill, turnyour front wheels toward the curb.

8 0

3 years ago