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3 years ago

Which two statements explain reasons to use a computer program to encode

Physics

2 answers:

Paraphin [41]3 years ago

8 0

Answer:a

Explanation:why not

mixas84 [53]3 years ago

3 0

Answer: A and B

Explanation: Because it makes the data you have secure and can only be authorized by you.

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People's perceptions of what is important in life are known as:

tangare [24]

Social perception (or person perception) is the study of how people form impressions of and make inferences about other people as sovereign personalities.A real-world example of social perception is understanding that others disagree with what one said when one sees them roll their eyes.

6 0

3 years ago

5. A man in a car is listening to the radio. The radio station is broadcasting at a frequency of 85 MHz from two radio transmitt

nasty-shy [4]

Answer:

Speed = 0.00392 m/s

Explanation:

Solution:

Frequency of the radio = 85 MHz

If we have the frequency, we can calculate the wavelength of the radio wave.

As we know,

Frequency = speed of light/wavelength

wavelength = c/f

c = speed of light = 3 x $10^{8}$ m/s

So,

Wavelength = 3 x $10^{8}$ m/s / 85 x $10^{6}$ Hz

Wavelength = 3.5294 m

Man gets disturbed reception at t = 15 min

t = 15 x 60 = 900 s

t = 900 s

Speed = distance/time

Here, distance is wavelength. So,

Speed = 3.5294 m / 900 s

Speed = 0.00392 m/s

Hence, the man's car is going with speed of 0.00392 m/s

3 0

3 years ago

What affects the vertical velocity of a projectile over time?<br>---

kobusy [5.1K]

The vertical velocity is affected by the acceleration of gravity (ignoring the effects of air resistance usually)

6 0

3 years ago

b) The distance of the red supergiant Betelgeuse is approximately 427 light years. If it were to explode as a supernova, it woul

Nat2105 [25]

Answer:

b) Betelgeuse would be $\approx 1.43 \cdot 10^{6}$ times brighter than Sirius

c) Since Betelgeuse brightness from Earth compared to the Sun is $\approx 1.37 \cdot 10^{-5} }$ the statement saying that it would be like a second Sun is incorrect

Explanation:

The start brightness is related to it luminosity thought the following equation:

$B = \displaystyle{\frac{L}{4\pi d^2}}$ (1)

where $B$ is the brightness, $L$ is the star luminosity and $d$ , the distance from the star to the point where the brightness is calculated (measured). Thus:

b) $B_{Betelgeuse} = \displaystyle{\frac{10^{10}L_{Sun}}{4\pi (427\ ly)^2}}$ and $B_{Sirius} = \displaystyle{\frac{26L_{Sun}}{4\pi (26\ ly)^2}}$ where $L_{Sun}$ is the Sun luminosity ( $3.9 x 10^{26} W$ ) but we don't need to know this value for solving the problem. $ly$ is light years.

Finding the ratio between the two brightness we get:

$\displaystyle{\frac{B_{Betelgeuse}}{B_{Sirius}}=\frac{10^{10}L_{Sun}}{4\pi (427\ ly)^2} \times \frac{4\pi (26\ ly)^2}{26L_{Sun}} \approx 1.43 \cdot 10^{6} }$

c) we can do the same as in b) but we need to know the distance from the Sun to the Earth, which is $1.581 \cdot 10^{-5}\ ly$ . Then

$\displaystyle{\frac{B_{Betelgeuse}}{B_{Sun}}=\frac{10^{10}L_{Sun}}{4\pi (427\ ly)^2} \times \frac{4\pi (1.581\cdot 10^{-5}\ ly)^2}{1\ L_{Sun}} \approx 1.37 \cdot 10^{-5} }$

Notice that since the star luminosities are given with respect to the Sun luminosity we don't need to use any value a simple states the Sun luminosity as the unit, i.e 1. From this result, it is clear that when Betelgeuse explodes it won't be like having a second Sun, it brightness will be 5 orders of magnitude smaller that our Sun brightness.

4 0

3 years ago

What is the kinetic energy of a toy truck with a mass of 0.75 kg and a velocity of 4 m/s? (Formula: )

Dvinal [7]

Answer: Option (b) is the correct answer.

Explanation:

Kinetic energy is the energy of an object or particle when it is in motion.

Mathematically, Kinetic energy = $\frac{1}{2}mass \times (velocity)^{2}$