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3 years ago

Describe what we may observe from Earth regarding the moon’s revolution around the earth and its rotation

1 answer:

4 0

When we look at the moon from the Earth, we always see the same light spots, dark spots, and shapes. It never changes. There could be two possible reasons for this:

-- The moon is a flat disk with some markings on it, and one side of it always faces the Earth.

-- The moon is a round ball with some markings on it, and one side of it always faces the Earth.

Either way, since the same side always faces the Earth, the only way that can happen is if the moon's revolution around the Earth and rotation on its axis both take EXACTLY the same length of time.

Even if they were only one second different, then we would see the moon's whole surface over a long period of time. But we don't. So the moon's rotation and revolution must be EXACTLY locked to the same period of time.

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three letters (JET) are placed in front of a plane mirror the image formed is in what arrangement???

mario62 [17]

Answer:

TEJ as this is a thing you wont get

3 0

3 years ago

Can anyone tell me which ones of these are true and which ones are false pls

Akimi4 [234]

There are two important facts to recall that will help answer this question:

1. The resistance of a segment of conducting wire is given by this equation:

R = ρL/A

ρ is the resistivity of the material making up the wire. This value is a constant that depends on the properties of the material. Resistivities for various materials can be found with a quick Google search.

L is the length of the wire.

A is the cross-sectional area of the wire.

From this equation you can tell that a wire's resistance will increase if it is made longer and/or thinner, and the resistance will decrease if it is made shorter and/or thicker. Mathematically speaking, the resistance is directly proportional to the length and inversely proportional to the cross-sectional area.

2. The other fact is that a conductor's resistance is also dependent on its temperature. Generally, as a conductor gets hotter, its resistance increases.

Let us now tackle the list of statements:

1. A shorter wire will allow electricity to move through at a higher rate than a longer wire.

According to the equation for a conductor's resistance, a shorter wire will have a smaller resistance.

Now recall that current is the movement of electric charges and Ohm's law:

V = IR

V is the applied potential difference between the ends of the wire.

I is the current.

R is the resistance.

Assuming you keep the potential difference constant, when you have a smaller resistance, you will have a larger current.

Statement 1 is correct.

2. A short, thick, cold wire is the best conductor.

According to the equation for a conductor's resistance, a shorter, thicker wire will have lesser resistance. A cold temperature will also help to keep the resistance low. A low resistance means a higher current.

Statement 2 is correct.

3. How well a material conducts current is an internal factor affecting resistance.

Statement 3 is correct, assuming the physical property in question is the material's resistivity. The resistivity is one of the factors in the equation for a conductor's resistance.

4. If you double the length of a wire, you cut the resistance in half.

According to the equation for a conductor's resistance, increasing the length of a wire increases the resistance. Statement 4 is false.

5. If you double the thickness of a wire, you cut the resistance in half.

According to the equation for a conductor's resistance, increasing the thickness of a wire decreases its resistance. Statement 5 is true.

6. Superconductors have no measurable resistance.

A superconductor by definition is able to conductor electric current with virtually no resistance. Statement 6 is true.

7. The higher the temperature of the conductor, the lower the resistance.

A conductor's resistance generally increases with temperature. Statement 7 is false.

8. The resistance in a wire with less thickness is less.

According to the equation for a conductor's resistance, making a wire thinner will increase its resistance. Statement 8 is false.

9. Thickness, length, and temperature are internal factors that affect resistance.

Thickness (cross-sectional area) and length are both factors in the equation determining a conductor's resistance. Temperature is also known as a factor that affects resistance. Statement 9 is true.

10. When a light is first switched on, the light bulb's filament has a lower resistance than after it gives off light for awhile.

A device that draws a current will generally heat up given sufficient time. This increases the device's resistance. Statement 10 is correct.

4 0

4 years ago

Read 2 more answers

Archimedes' principle can be used to calculate the density of a fluid as well as that of a solid. suppose a chunk of iron with a

ella [17]

<span>(a) 39.5 g (b) 49.53 cm^3 (c) 0.7975 g/cm^3, liquid is an alcohol (a) This will be the difference between the weight of the iron in air and the weight submerged in fluid. So: 390.0 g - 350.5 g = 39.5 g (b) The density of iron is 7.874 g/cm^3, so the volume of the iron chunk is 390.0 g / 7.874 g/cm^3 = 49.53 cm^3 (c) The density of the fluid will be the mass of the fluid divided by the volume, so: 39.5 g / 49.53 cm^3 = 0.7975 g/cm^3 Since the density is very dependent upon the temperature and since the temperature wasn't specified, the actual substance can't be completely identified. Although some candidates are: 1. Mixture of Alcohol and water. Density ranges from 0.785 g/cm^3 to 1.000 g/cm^3. 2. Crude oil. Density 0.790 g/cm^3 3. Hydrazine. Density 0.795 g/cm^3 4. Methanol. Density 0.791 g/cm^3 5. Ocimene. Density 0.798 g/cm^3 The most likely candidate is a high concentration of an alcohol of some sort.</span>

5 0

3 years ago

How can we use earths resources sustainability

erik [133]

.Water
Adequate water supplies of high quality are necessary both for community use and local ecosystems. Communities and jurisdictions must work together to assure an adequate water supply to meet future needs. This section presents resources to aid in that effort.Energy
Communities require energy. Nonrenewable sources for power generation, home and workplace, and transportation cause pollution and its harmful impacts. Energy conservation and the use of renewable fuels provide cost-effective and more sustainable alternatives. This section contains resources available to make energy use more efficient.Air and Climate
Both the natural ecosystem and human health can be adversely impacted by declining air quality and climatic change. Communities can preserve air quality by limiting or eliminating the discharge of harmful chemicals into the air and by minimizing the sources of air pollution. This section contains resources and approaches that address air quality and climate change.Biodiversity
Biodiversity is particularly important for creating sustainability because of the specialized roles each species plays in maintaining ecological balance. Communities can promote healthy wildlife by supporting integrative approaches for managing, protecting, and enhancing wildlife populations and habitats appropriate to their area. Some examples are given here.Land, Forests, and Ecosystems
While providing a protective covering for soil, water, and the atmosphere, forests are also renewable sources of an endless variety of products. In a healthy ecosystem, policies and programs must balance economic and conservation needs. This section highlights cases where communities have developed land use practices and businesses that both conserve ecosystems and enhance local economies.

7 0

3 years ago

A generator rotates at 95 Hz in a magnetic field of 0.025 T. It has 550 turns and produces an rms voltage of 170 V and an rms cu

weeeeeb [17]

Answer:

Peak current= 84.86 A

Area of each turn = 0.029 m^2

Explanation:

The peak value of current can be obtained from Irms= 0.707Io. Where Io is the peak current.

Hence;

Irms= 60.0A

Io= Irms/0.707

Io = 60.0/0.707

Io= 84.86 A

Vrms= 0.707Vo

Vo= Vrms/0.707= 170/0.707 = 240.45 V

From;

V0 = NABω

Where;

Vo= peak voltage

N= number of turns

B= magnetic field

A= area of each coil

ω= angular velocity

But ω= 2πf = 2×π×95= 596.9 rads-1

Substituting values;

A= Vo/NBω

A= 240.45/550×0.025×596.9

A= 0.029 m^2

6 0

4 years ago