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3 years ago

Motion is always compared to something called

1 answer:

7 0

Movement can be without change in positions. As only a part of it can be made to move. If you move there is a motion and if there is a motion there is a movement so they're same thing. In motion whole of body moves, but in movements only the parts of body moves.

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Which term describes the number of joules used per second by a circuit?

jasenka [17]

Answer:

B) Power

Explanation:

The power is defined by the following equation:

P = W / t

where:

W = work = Force * Distance = [Newton] * [meter]

t = time = seconds

The units for work are give en Newton per second, which is equal to Joules

And for power the unit used commonly is Watts, therefore:

Watts = (Joule/second)

5 0

3 years ago

Read 2 more answers

Which equation correctly relates mechanical energy, thermal energy and total of energy when there is friction present in the sys

agasfer [191]

Answer:

E total = ME + E thermal

Explanation:

APEX

4 0

3 years ago

Which of the following best describes the human population from early times to the present?

Makovka662 [10]

Answer:

We have a not significant increase of the population until 1700s or 1800s and then a significant increase growth from these years to the present.

Explanation:

From the figure attached we see the evolution of the human population since early times (1050).

We see that from 1050 until 1750-1850 we have an increase slowly with a low value for the increase per year.

But after these years (1750-1850) we see a considerable increase of the population, like an exponential model.

So then we can conclude in general terms this:

We have a not significant increase of the population until 1700s or 1800s and then a significant increase growth from these years to the present.

7 0

3 years ago

Radiation from the Sun The intensity of the radiation from the Sun measured on Earth is 1360 W/m2 and frequency is f = 60 MHz. T

Zina [86]

a) Total power output: $3.845\cdot 10^{26} W$

b) The relative percentage change of power output is 1.67%

c) The intensity of the radiation on Mars is $540 W/m^2$

Explanation:

The intensity of electromagnetic radiation is given by

$I=\frac{P}{A}$

where

P is the power output

A is the surface area considered

In this problem, we have

$I=1360 W/m^2$ is the intensity of the solar radiation at the Earth

The area to be considered is area of a sphere of radius

$r=1.5\cdot 10^{11} m$ (distance Earth-Sun)

Therefore

$A=4\pi r^2 = 4 \pi (1.5\cdot 10^{11})^2=2.8\cdot 10^{23}m^2$

And now, using the first equation, we can find the total power output of the Sun:

$P=IA=(1360)(2.8\cdot 10^{23})=3.845\cdot 10^{26} W$

The energy of the solar radiation is directly proportional to its frequency, given the relationship

$E=hf$

where E is the energy, h is the Planck's constant, f is the frequency.

Also, the power output of the Sun is directly proportional to the energy,

$P=\frac{E}{t}$

where t is the time.

This means that the power output is proportional to the frequency:

$P\propto f$

Here the frequency increases by 1 MHz: the original frequency was

$f_0 = 60 MHz$

so the relative percentage change in frequency is

$\frac{\Delta f}{f_0}\cdot 100 = \frac{1}{60}\cdot 100 =1.67\%$

And therefore, the power also increases by 1.67 %.

In this second case, we have to calculate the new power output of the Sun:

$P' = P + \frac{1.67}{100}P =1.167P=1.0167(3.845\cdot 10^{26})=3.910\cdot 10^{26} W$

Now we want to calculate the intensity of the radiation measured on Mars. Mars is 60% farther from the Sun than the Earth, so its distance from the Sun is

$r'=(1+0.60)r=1.60r=1.60(1.5\cdot 10^{11})=2.4\cdot 10^{11}m$