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3 years ago

What are 5 examples of expansion and contraction? What are their benefits?

Physics

1 answer:

liubo4ka [24]3 years ago

6 0

Answer:

If you hold a hot glass tumbler under cold water, it will crack

Explanation:

This is because the outer surface of the glass comes in direct contact with cold water and contracts more compared to the inner surface.

This is one example I know.

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Select the correct answer.

Sergeeva-Olga [200]

Answer:

All of the above.

Explanation:

All of these steps are useful towards getting a job.

8 0

3 years ago

What are some ways that electric fields are similar to magnetic fields?

sattari [20]

Answer:

The correct answers are the proportionality of the fields concerning distance, vector fields, and forces at a distance.

Explanation:

The similarities between magnetic fields and electric fields are that electric fields are produced by two charges that can be positive and negative. Magnetic fields are associated with two magnetic poles, although they are also produced by moving charges. Both fields are inversely proportional to the square of the distance between the sources, both fields are vectorial and both act by distant forces.

Have a nice day!

3 0

3 years ago

Where is potential energy in food stored

AlexFokin [52]

The potential energy is stored in the chemical bonds of the food. When those bonds break up during the metabolic processes, the energy is released. After that, that energy is stored in the Adenosine Triphosphate bonds aka ATP. The simplest way to think is to think of food as the tightly bound atoms. When the chemical bonds between those atoms break, the stored energy in that food is released.

6 0

3 years ago

A cell phone weighing 80 grams is flying through the air at 15 m/s. What is its kinetic energy

Contact [7]

Answer:

The kinetic energy of the cell phone is 9J

Explanation:

The kinetic energy is the energy possessed by a body by virtue of motion.

The kinetic energy is expressed as

KE= 1/2m(v)²

Given data

Mass of cell phone m= 80g--to kg=80/1000= 0.08kg

Velocity of cell phone v= 15m/s

Substituting our given data we have

KE= 1/2*0.08(15)²

KE= (0.08*225)/2

KE=18/2

KE= 9J

8 0

3 years ago

The two speakers at S1 and S2 are adjusted so that the observer at O hears an intensity of 6 W/m² when either S1 or S2 is sounde

Zanzabum

Answer:

The minimum frequency is 702.22 Hz

Explanation:

The two speakers are adjusted as attached in the figure. From the given data we know that

$S_1 S_2$ =3m

$S_1 O$ =4m

By Pythagoras theorem

$S_2O=\sqrt{(S_1S_2)^2+(S_1O)^2}\\S_2O=\sqrt{(3)^2+(4)^2}\\S_2O=\sqrt{9+16}\\S_2O=\sqrt{25}\\S_2O=5m$

Now

The intensity at O when both speakers are on is given by

$I=4I_1 cos^2(\pi \frac{\delta}{\lambda})$

Here

I is the intensity at O when both speakers are on which is given as 6 $W/m^2$

I1 is the intensity of one speaker on which is 6 $W/m^2$

δ is the Path difference which is given as

$\delta=S_2O-S_1O\\\delta=5-4\\\delta=1 m$

λ is wavelength which is given as

$\lambda=\frac{v}{f}$

Here

v is the speed of sound which is 320 m/s.

f is the frequency of the sound which is to be calculated.

$16=4\times 6 \times cos^2(\pi \frac{1 \times f}{320})\\16/24= cos^2(\pi \frac{1f}{320})\\0.667= cos^2(\pi \frac{f}{320})\\cos(\pi \frac{f}{320})=\pm0.8165\\\pi \frac{f}{320}=\frac{7 \pi}{36}+2k\pi \\ \frac{f}{320}=\frac{7 }{36}+2k \\\\ {f}=320 \times (\frac{7 }{36}+2k )$

where k=0,1,2

for minimum frequency $f_1$ , k=1

${f}=320 \times (\frac{7 }{36}+2 \times 1 )\\\\{f}=320 \times (\frac{79 }{36} )\\\\ f=702.22 Hz$

So the minimum frequency is 702.22 Hz

5 0

3 years ago