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3 years ago

What is the speed of sound at the atmospheric temperature of 30°C?

Physics

2 answers:

Rina8888 [55]3 years ago

5 0

Answer:

Option C is the correct answer.

Explanation:

The speed of sound in air is given approximately by

$v=331.4+0.6T_c$

Here $T_c$ is the temperature in degree Celsius.

Temperature $T_c=30^0C$

Substituting we will get

v = 331.4 + 0.6 x 30 = 349.4 m/s

Option C is the correct answer.

12345 [234]3 years ago

4 0

The parcel will undergo projectile motion, which means that it will have motion in both the horizontal and vertical direction.

First, we determine how long the parcel will fall using:

s = ut + 1/2 at²

where s will be the height, u is the initial vertical velocity of the parcel (0), t is the time of fall and a is the acceleration due to gravity.

5.5 = (0)(t) + 1/2 (9.81)(t)²

t = 1.06 seconds

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A sound wave traveling through dry air has a frequency of 15 Hz, a

Korolek [52]

Answer:

Option B

Explanation:

Speed of a wave is denoted by:

v=fλ

where f is the frequency which is unchanged 15Hz and λ is the new wavelength which is 28m

v=fλ

$v=15(28)\\v=420m/s$

3 0

3 years ago

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Which best explains why people see carrots as orange

Andru [333]

Beta Carotene is the reason why a carrot is orange. Carotene is a color pigment that is found in large quantities in carrots and it has health benefits as well. The main health benefit of carotene is that our body converts it into vitamin A which is essential.

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3 years ago

Read 2 more answers

(a) Consider the initial-value problem dA/dt = kA, A(0) = A0 as the model for the decay of a radioactive substance. Show that, i

murzikaleks [220]

Answer:

a) $t = -\frac{ln(2)}{k}$

b) See the proof below

$A(t) = A_o 2^{-\frac{t}{T}}$

c) $t = 3T \frac{ln(2)}{ln(2)}= 3T$

Explanation:

Part a

For this case we have the following differential equation:

$\frac{dA}{dt}= kA$

With the initial condition $A(0) = A_o$

We can rewrite the differential equation like this:

$\frac{dA}{A} =k dt$

And if we integrate both sides we got:

$ln |A|= kt + c_1$

Where $c_1$ is a constant. If we apply exponential for both sides we got:

$A = e^{kt} e^c = C e^{kt}$

Using the initial condition $A(0) = A_o$ we got:

$A_o = C$

So then our solution for the differential equation is given by:

$A(t) = A_o e^{kt}$

For the half life we know that we need to find the value of t for where we have $A(t) = \frac{1}{2} A_o$ if we use this condition we have:

$\frac{1}{2} A_o = A_o e^{kt}$

$\frac{1}{2} = e^{kt}$

Applying natural log we have this:

$ln (\frac{1}{2}) = kt$

And then the value of t would be:

$t = \frac{ln (1/2)}{k}$

And using the fact that $ln(1/2) = -ln(2)$ we have this:

$t = -\frac{ln(2)}{k}$

Part b

For this case we need to show that the solution on part a can be written as:

$A(t) = A_o 2^{-t/T}$

For this case we have the following model:

$A(t) = A_o e^{kt}$

If we replace the value of k obtained from part a we got:

$k = -\frac{ln(2)}{T}$

$A(t) = A_o e^{-\frac{ln(2)}{T} t}$

And we can rewrite this expression like this:

$A(t) = A_o e^{ln(2) (-\frac{t}{T})}$

And we can cancel the exponential with the natural log and we have this:

$A(t) = A_o 2^{-\frac{t}{T}}$

Part c

For this case we want to find the value of t when we have remaining $\frac{A_o}{8}$

So we can use the following equation:

$\frac{A_o}{8}= A_o 2^{-\frac{t}{T}}$

Simplifying we got:

$\frac{1}{8} = 2^{-\frac{t}{T}}$

We can apply natural log on both sides and we got:

$ln(\frac{1}{8}) = -\frac{t}{T} ln(2)$

And if we solve for t we got:

$t = T \frac{ln(8)}{ln(2)}$

We can rewrite this expression like this:

$t = T \frac{ln(2^3)}{ln(2)}$

Using properties of natural logs we got:

$t = 3T \frac{ln(2)}{ln(2)}= 3T$

8 0

3 years ago

What would happen if a proton were added to the nucleus of the atom? (Check all that apply)

katen-ka-za [31]

Answer:

It would become a different element.

Explanation:

When you change the number of protons i.e, add a proton in the nucleus of an atom, you will change the atom from one element to a different element and also positive charge of the atom also increased by 1.

For example, adding a proton to the nucleus of an atom of hydrogen creates an atom of helium.

So, we conclude that by adding a proton the atom will change from one element to another element.

3 0

3 years ago

Whitch family has full valence energy level

levacccp [35]

Group 0 - they are called the NOBLE GASES
(as they're very unreactive) because...

ALL of their atoms are full.
Example : Helium contains 2 electrons so it's outer shell is full

7 0

3 years ago