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Juliette [100K]
3 years ago
9

An extraterrestrial "Eratosthenes" performs the equivalent experiment, that Eratosthenes did on Earth, on her/his home world. Sh

e/He measures the angle of the shadow in her/his alien hometown (Alexandria) to be 10 degrees and the distance to the alien well (Syene) to be 500 km. What is the radius that the alien Eratosthenes estimates for her/his planet?
a. 2865 km
b. 9065 km
c. 18024 km
d. 1500 km
e. 31415 km
Physics
1 answer:
Bad White [126]3 years ago
6 0

Answer:

a. 2865 km

Explanation:

Eratosthenes observed that the sun's rays formed a vertical angle of 7º 12 ’. Which confirmed that the Earth was not flat, assuming that it had a spherical shape, using the distance between Alexandria and Siena and the measure of the angle of inclination of the solar rays in Alexandria, calculated the circumference of the Earth.

The calculation was made with a simple rule of three:

angle of inclination of the solar rays——————- distance

               360º                                   ————- Planet circumference

C=\frac{distance*360^\circ}{angle}\\\\C=\frac{500km*360^\circ}{10^\circ}=18000km

And since we know that:

C=2\pi R\\\\R=\frac{C}{2\pi}\\\\R=\frac{18000km}{2\pi}=2865km

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4) The mass of Pluto is 1.31 x 1022 kg and its radius is 1.15 x 106 m. What is the acceleration of
Elina [12.6K]

Answer:

0.661 m/s²

Explanation:

g = MG / r²

g = (1.31×10²² kg) (6.67×10⁻¹¹ m³/kg/s²) / (1.15×10⁶ m)²

g = 6.61×10⁻¹ m/s²

g = 0.661 m/s²

3 0
3 years ago
Which process is represented by the PV diagram?
Reika [66]

Hi!


The answer would be A. Isobaric Process


<h3>Explanation:</h3>

Isobaric process is a process where the pressure inside a system remains unchanged. In the Pressure Volume graph given, you can see that the pressure (y axis) remains constant with an increasing volume ( x axis). An example of this would be heating a container with a movable piston. Now, the degree of pressure is dependent on the frequency of collisions of particles inside a system on the walls. If this frequency changes, the pressure changes (proportionally). In our example, heating a container with a movable piston results in the particles inside the container to gain kinetic energy and move faster, meaning an increased frequency of collisions (higher pressure), but at the system time the increase in pressure results in the piston being pushed outwards, causing the volume of the container to increase. This results in decreased frequency of collision of the particles with the walls of the container (lesser pressure). This results in the a zero net effect on the pressure.


Hope this helps!

3 0
3 years ago
How long must a flute be in order to have a fundamental frequency of 262 Hz (this frequency corresponds to middle C on the evenl
spin [16.1K]

Answer:

L=0.654 m

Explanation:

<u>Concepts and Principles  </u>

1- The speed of sound in air is expressed as a function of the temperature of air as follows:  

 v=(331 m/s)√(1+T_C/273°C)                        (1)

where 331 m/s is the speed of sound in air at temperature 0°C and Tc is the temperature of air in Celsius.  

<u>Standing Wave Patterns in Pipes:  </u>

A pipe open at both ends can have standing wave patterns with resonant frequencies:  

f=v/λ=nv/2L                     n=1,2,3.........

where v is the speed of sound in air.  

<u>Given Data </u>

f_1 (fundamental frequency of the flute) = 262 Hz

T (temperature of the air) = 20°C  

The flute is open at both ends.  

<u>Required Data </u>

We are asked to determine the length of the tube.  

<u>Solution</u><u>  </u>

The speed of sound in air at temperature T = 20°C is found from Equation (1):

 v=(331 m/s)√(1+T_C/273°C)  

 =342.91 m/s

The fundamental frequency of the flute is found by substituting n = 1 into Equation (2):  

f=v/2L

Solve for L:  

L=v/2f_1

L=0.654 m

7 0
2 years ago
A planet’s gravity is related to which of the following? (Points : 5)
katovenus [111]

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-- One possible cause of deforestation is the removal of trees without
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-- Electromagnetic energy can be defined as energy that moves at
the speed of light.  If you conduct experiments to determine whether
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you find that it behaves as both.</span>


4 0
2 years ago
What information and measurements would you need to calculate the rate of movement?
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So, for the first variety, you would need distance and time to measure the rate of how far you go at a certain time. It is also called as velocity. For the second variety, you would need velocity and time to measure the rate of how fast you are going at a certain interval. It is also called as acceleration.
8 0
3 years ago
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