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3 years ago

1. Most waves are caused by vibrations. What motion in a transmitting antenna causes the vibrations that produce radio waves?

2 answers:

8 0

The answer 1 is
The best-known use of radio waves is for communication; television, cellphones and radios all receive radio waves and convert them to mechanical vibrations in the speaker to create sound waves that can be heard.Electromagnetic radiation is transmitted inwaves or particles at different wavelengths and frequencies.

the answer 2 is

Radio Waves: Instant Communication
Microwaves: Data and Heat

i think the answer number 3 is
It is all about wavelength versus tunnel diameter. The wavelength of GPS is about 20cm it would happily propagate in any normal tunnel if it could get in but the earth and other structures absorb it. AM radio (600kHz - 1500kHz) cannot propagate in any normal tunnel because the wavelength is too long (500m-200m) relative to the diameter, and thus gets reflected at the entrance. FM (100MHz ~ 3m) would propagate and it does for a while but then it suffers reflections

Sladkaya [172]3 years ago

3 0

Answer:

1.Oscillatory motion : this is the to and fro movement of wave signals from the antenna

2.a.Microwave Oven- produces microwaves

b.. Light bulb-produces visible light

3.Radio signals does not pass through a solid barrier in the dark. Just like how light can't pass through a rock. The radio signals are restored as the car gets to the entrance of the tunnel

Explanation:

Waves is a disturbance which travels displacement and transfers energy without displacing the medium itself

Most waves are caused by vibrations. What motion in a transmitting antenna causes the vibrations that produce radio waves?

Oscillatory motion : this is the to and fro movement of wave signals from the antenna

2. Name two common household appliances that produce electromagnetic waves other than radio waves. What kind of electromagnetic waves do they produce?

a.Microwave Oven- produces microwaves

b.. Light bulb-produces visible light

3.When you are in a car and it passes through a tunnel, the radio signal is sometimes lost. Why do you think this happens?

Radio signals does not pass through a solid barrier in the dark. Just like how light can't pass through a rock. The radio signals are restored as the car gets to the entrance of the tunnel

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3. A cat pushes a 0.25-kg toy with a net force of 8 N. According to Newton's second

jek_recluse [69]

Mass=0.25kg
Force=8N

$\\ \sf{:}\!\implies F=ma$

$\\ \sf{:}\!\implies Acceleration=\dfrac{F}{m}$

$\\ \sf{:}\!\implies Acceleration=\dfrac{8}{0.25}$

$\\ \sf{:}\!\implies Acceleration=32m/s^2$

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3 years ago

The brain mass of a human fetus during a particular trimester can be accurately estimated from the circumference of the head by

Paladinen [302]

Answer:

a. If c = 20 cm, then the mass of the brain is m = 5 g.

b. At c = 20 cm, the brain's mass is increasing at a rate of 15.75 g/cm.

Explanation:

From the equation

$m\left(c\right) = \frac{c^3}{100}-\frac{1500}{c}$

we have

a. for c = 20 cm

$m\left(20\right)=\frac{20^3}{100}-\frac{1500}{20}=5,$

then the mass is m(20) = 5 g.

b. In order to find the rate of change, first we derivate

$\frac{dm}{dc}=\frac{3c^2}{100}+\frac{1500}{c^2}.$

Evaluated at c = 20 cm, we have

$\frac{dm}{dc}|_{c=20}=\frac{3\times 20^2}{100}+\frac{1500}{20^2}=15.75.$

So, at c = 20 cm, the mass of the brain is increasing at a rate of 15.75 g/cm.

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3 years ago

The distance and displacement of a object in motion can be the same (true or false)

Rasek [7]

Aswer:

False, the values of the distance traveled and the displacement only coincide when the trayectorie is a straight line. Otherwise, the distance will always be greater than the offset.

Although these terms are used synonymously in other cases, they are totally different. Since the distance that a mobile travels is the equivalent of the length of its trajectory. Whereas, the displacement will be a vector magnitude.

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3 years ago

Which tool would you use to measure the amount of rainfall?

zheka24 [161]

Answer:

Explanation:

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3 years ago

Read 2 more answers

Add these measurements, using significant digit rules:

tia_tia [17]

Here we have to add the two measurements given in the question

The measurement values are given as 1.0090 cm and 0.02 cm.we have to add them on the basis of significant figure rules.

As per the addition rule in terms of significant figures

1-First we have to select the number of significant digits after the decimal point of each quantity.

2-Now we have to remember that during the addition ,the resultant of two quantities will follow the quantity having least number of significant figures after the decimal point.

3-Here we are considering the minimum number of significant figures after the decimal points not the minimum number of significant figures in case of multiplication and division

Now we have to add these two quantities as per the above rule-

1.0090 cm +0.02 cm

=1.0290 cm

Here the result will follow 0.02 which has minimum number of significant figures after the decimal points.

Hence we have to round off the number from 9 of 1.0290

As 9 is greater than 5 ,so he actual result will be 1.03 cm

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3 years ago