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2 years ago

How are lasers used to determine the distance from earth to the moon?

2 answers:

5 0

A beam of laser is directed at a reflecting surface put on the moon when the beam of laser is reflected a receiver on the each measure the time since the beam was sent till it was received. Laser is simply light so it has constant velocity in vacuum ~ air (c = 3 x 10^8 m/s)

to find the distance:

t : time measured between launching the beam and receiving it

d : distance

d = ct

Over [174]2 years ago

3 0

Explanation :

Lasers are used to determine the distance from earth to the moon. It is known as the Lunar Laser Ranging experiment. Laser is nothing but a a light source.

This can be done by passing a flash of light towards the moon. A reflector is placed on the surface of moon by the members of Apollo mission. With the help of this reflector light is reflected back to the earth.

The time taken by the light to travel the surface of moon and back to earth is calculated. It was approximately 2.55 seconds. So, for one side time is 1.275 seconds.

We know that the speed of light is c i.e. $3\times 10^8\ m/s$ .

Distance from Earth to the Moon is, d = c t

So, $d=3\times 10^8\ m/s \times 1.275\ s$

$d=3.825\times 10^8\ m$

$d=382500\ Km$

Hence, this is the required solution.

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Which two elements will most likely form an ionic bond? (Click on the periodic table icon to view these elements) krypton and li

netineya [11]

Answer:

Magnesium and Bromine

Explanation:

I just took the test, and Magnesium has 7 electrons and Bromine has 2 valance electrons making the transfer a lot easier. In the first choice, Krypton already has 8 valance electrons therefore it cannot transfer or accept any more which rules it out as a possible answer. Calcium has 2 valance electrons and Potassium has 1 meaning it couldn't make a full shell of 8 and cannot make a ionic bond. Iodine has 7 electrons as well as Chlorine which wouldn't be the answer because it would have more than 8 valance electrons.

4 0

2 years ago

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If the temperature of an iron sphere is increased A)its density will decrease .B)its volume will decrease. C)its mass will decre

babymother [125]

Answer:

A) Its density will decrease

Explanation:

When an object is heated, its volume increases. This is due to the fact that the particles in the medium vibrate more (if it is a solid) or they move more (if it is a liquid or a gas), therefore they tend to occupy a larger space.

At the same time, the mass of the object does not change, because the mass just represents the amount of matter contained in the object, so it does not increase/decrease at different temperatures.

The density of an object is defined as the ratio between the mass (m) and the volume (V):

$d=\frac{m}{V}$

We said that the mass remains unchanged while the volume increases: since the density is inversely proportional to the volume, this means that the density decreases.

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2 years ago

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An aircraft travels a distance of 50km in a straight line

Juliette [100K]

Answer:

200 m/s

Explanation:

v = distance / time = 50km/250s = 50000m/250s = 200 m/s

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2 years ago

If 7 ounces of a sports drink contains 110 milligrams of sodium, what is the total number of milligrams of sodium in 20 ounces o

ehidna [41]

so you just take 110 divided by 7 and then you get the answer and times tthat by 20 and you get you answer which is 314.28 milligrams of sodium in 20 ounces of the sports drink.

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2 years ago

In an intergalactic competition, spaceship pilots compete to see who can cover the distance between two asteroids in the short-

pogonyaev

Answer:

a) truc is C, b) correct result is the B

Explanation:

As the speed of the competition is very high, for the judges the speed is

v = d / t

v = 3 109 m / 20

v = 1.5 108 m / s

This is half the speed of light. For these high speeds we must use the relations of special relativity.

For the time t = to γ

For distance L = Lo / γ

γ = √ (1-v2 / c2)

Own time and distance (to and Lo) corresponds to the observer who is not moving the judges in this case

Let's look for the range value

γ = 1 / √ (1 - (1.5 / 3) 2) = 1 / 0.866 = 1.15

The time t = 20 1.15 = 23 s

The distance L = 3 10 9 /1.15 = 2.60 109 m

From these results we see that time increases and the distance is shorter.

Let's review the claims

A) False. It's the opposite

B) False

C) True. It is according to the result found

D) False.

In the nuclear fusion process, we will also use the special relativity that has a relationship between energy and mass

ΔE = c² Δm

As in the process energy is released, for the law of conservation of the mass of energy to be fulfilled, the total mass of the products, He atom, must be reduced.

Therefore the correct result is the B

4 0

3 years ago