what does it mean to say that momentum is conserved

Answer:

Length of one stadium = 0.1556 km

Explanation:

We have the diameter of Earth = 12740 km

Thus, circumference (C) of Earth is

[tex]=2\pi \frac{Diameter}{2} \\[/tex]

[tex]=2\times \pi \times \frac{12740}{2}[/tex]

C = 40023.89 km

Eratosthenes was a Greek polymath. He was the first to calculate the circumference of Earth. He had observed that at local noon on day of Summer Solstice, when Sun is overhead for the locations on Tropic of Cancer, a place named Syene had zero shadow day. Also on the same day the objects in Alexandria casts shadow. This proved that Earth is spherical and not flat. He went further and calculated the Sun angle ([tex]\theta[/tex]) for Alexandria by using a Rod (Gnomon). He found the angle to be about 7°. He also knew the distance (D) between Alexandria and Syene which was 5000 Stadia.

Lets say length of one stadia = S km

He used this data and simple concept of geometry as given below:

[tex]\frac{\theta }{360}=\frac{D}{C}[/tex]

[tex]=\frac{7}{360}=\frac{5000 \times S}{40023.89}[/tex]

[tex]=5000 \times S = \frac{7\times 40023.89}{360}[/tex]

[tex]=S = \frac{7\times 40023.89}{360\times5000}[/tex]

S = 0.1556 km

Answer

Correct answer is Spring

Explanation

In southern hemisphere there are four seasons which are as follows

Spring

spring begins in the month of September

Summer

summer begins in the month of December

Autumn

autumn begins in the month of March

Winter

winter begins in the month of June.

spring

its the correct answer on the test,, goodluckk :)!

The orbital motion is slower and gravitational attraction is weaker.

Kepler's law of planetary motion states that, the line joining a  planet and the sun sweeps equal areas in equal intervals of time. That means, as the  planet approaches the sun it speeds up and as it moves away from the sun, it  slows down.

Here,

The planet is farther from the sun.

According to Kepler's law of planetary motion, the speed of this planet is decreasing. So, its orbital motion becomes slower and as the distance between the planet  and the sun increases, the gravitational attraction between them also becomes weak.

Hence,

The orbital motion is slower and gravitational attraction is weaker.

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Answer:

Correct answer is c

Explanation:

the main purpose of the nervous system is relaying messages between the body and the brain

Relating messages between the body and brain is the main purpose of the nervous system in the human body. So, the correct option is C.

The nervous system is defined as a highly complex part of an animal that coordinates its functions and sensory information by transmitting signals from different parts of its body. The nervous system transmits signals between the brain and the rest of the body which includes the internal organs.

The activity of the nervous system controls the ability to move, breathe, see, think, and many more where the basic unit of the nervous system is a nerve cell or neuron. Relating messages between the body and brain is the main purpose of the nervous system in the human body.

Therefore, the correct option is C.

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Answer:

CME

Explanation:

They right^ aced the test

Answer:

The organelle missing from E.coli is nuclear membrane.

Explanation:

A nuclear membrane is a double membrane that surrounds and protects the nucleus of a cell. The nuclear membrane is lacking because there is no need for one to protect a nucleus that does not exist. Bacteria cells are also prokaryotes, and all prokaryotes lack a nucleus.

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Answer:The substance;

- must possess poles (north and south)

- exhibit force of attraction and repulsion i.e obeys law of magnetism)

Explanation:

For a substance to be considered a magnet, such magnet must be able to attract metallic objects to itself when placed in a magnetic field.

The substance must possesses free north and south poles at its ends because magnets generally possesses both the force of attraction and repulsion which is dependent on the nature of the poles of the magnetic substances coming together. Like poles of magnets (same poles) are known to repel each other while unlike poles (different poles) of magnets attracts each other

A substance is considered a magnet if it can generate a magnetic field and has both north and south poles. Magnetic fields are created by the movement of electric charges or inherent magnetic properties. In ferromagnetic substances, magnetic domains align in a manner that produces a large-scale magnetic field.

To be considered a magnet, a substance must satisfy two essential criteria. Firstly, it needs to generate a magnetic field, which is an invisible force field that exerts a force on other ferromagnetic materials and moving electric charges. The magnetic field is produced either by the movement of electric charges or by intrinsic magnetic properties of the substance itself.

Secondly, a magnet must have both north and south poles. This is a fundamental property of all magnets: if you were to cut a bar magnet in half, you would end up with two smaller magnets, each with its own north and south pole. The two poles represent the directionality of the magnetic field - it emanates from the north pole and loops back into the south pole.

Common types of magnets, such as ferromagnets, achieve these properties through their structure at an atomic level. In ferromagnetic materials, small regions known as magnetic domains are created where atoms are grouped together with their magnetic dipoles aligned in the same direction, producing a noticeable large-scale magnetic field.

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Answer:

It is moving away from Earth.

Explanation:

As the source comes closer to the observer then we can say that its frequency will increase.

So here we know that

[tex]\frac{\Delta \nu}{\nu} = \frac{v}{c}[/tex]

here we know that

v = speed of the star

c = speed of light

now if we know that speed of the star is towards us then the frequency will increase and hence the wavelength will decrease.

So it is known as Blue shift

While if the star is moving away from us then in that case the frequency will decrease and hence the wavelength will increase.

So here it is known as Red Shift.

So here correct answer will be

It is moving away from Earth.

Answer: The frequency of Wave 2 is double the frequency of Wave 1.

Answer:

A) [tex]v = \frac{2\pi r}{T}[/tex]

Explanation:

As we know that the speed of the object is defined as the the ratio of total distance and total time taken

now as we know that here the distance along the path of the orbiting object is total length of the circle

so it is given as

[tex]L = 2\pi r[/tex]

also we know that

time period to complete the orbit is given as

[tex]t = T[/tex]

now the speed is given as

[tex]v = \frac{d}{t}[/tex]

[tex]v = \frac{2\pi r}{T}[/tex]

Answer:

The shape will be elliptical hopefully this helps!

Answer:

Explanation:

The sound of a ringing cellphone could not be transmitted or heard if the cellphone is enclosed in some sort of closed container from which the air has been removed.  Sound is a mechanical wave, and so it must have some material substanceto travel through.  Otherwise sound cannot travel from one place to another.  The sound of the ringing could not travel through the vacuum inside the container if all the air were removed.

4.53 billion years

1.653 trillion days

39.68 trillion hours

2.381 × 10^15 minutes

1.429 × 10^17 seconds

Answer:

4.53 billion years old

Explanation:

Moon is considered to be formed about 60 million years later to the formation of the solar system. The rocks brought from surface of moon suggest its age to be about 4.53 billion years. The Giant-impact hypothesis suggests that moon was formed when a Mars sized object collided with the Earth, the debris accreted to from the moon.

Answer:

D  The water absorbs energy which causes the water molecules to have more kinetic and potential energy, changing their configuration from a liquid to a gas.

Explanation:

Good Luck ^^

The water absorbs energy which causes the water molecules to have more kinetic and potential energy, changing their configuration from a liquid to a gas. The correct option is D.

The energy an object has as a result of motion is known as kinetic energy. A force must be applied to an object in order to accelerate it.

We must put in effort in order to apply a force. After the work is finished, energy is transferred to the item, which then moves at a new, constant speed.

Energy is absorbed by the water, increasing the kinetic and potential energy of the water molecules and converting them from a liquid to a gas.

Water molecules usually have the highest kinetic energy in the steam phase.

Thus, the correct option is D.

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