Answer:
Use of telemetry and radar astronomy
Explanation:
An astronomical Unit (AU) is a unit of measuring distances in outer space, which is based on the approximate distance between the earth and the Sun.
After several years of trying to approximate the distance between the Sun and the Earth using several methods based on geometry and some other calculations, advancements in technology made available the presence of special motoring equipment, which can be placed in outer space to remotely monitor and measure the position of the sun.
The use of direct radar measurements to the sun (radar astronomy) have also made the determination of the AU more accurate.
A standard radar pulse of known speed is sent to the Sun, and the time with which it takes to return is measured, once this is recorded, the distance between the Earth and the Sun can be calculated using
distance = speed X time.
However, most of these means have to be corrected for parallax errors
Use this formula to find your answer...
Determine the frequency of a clock waveform whose period is 2us or (micro) and 0.75ms
frequency (f)=1/( Time period).
Frequency of 2 us clock =1/2*10^-6 =10^6/2 =500000Hz =500 kHz.
Frequency of 0..75ms clock =1/0.75*10^-3 =10^3/0.75 =1333.33Hz =1.33kHz.
The frequency of the wave is 6800 Hz
<u>Explanation:</u>
Given:
Wave number, n = 20
Speed of light, v = 340 m/s
Frequency, f = ?
we know:
wave number = 
Therefore, the frequency of the wave is 6800 Hz
Answer:
1470kgm²
Explanation:
The formula for expressing the moment of inertial is expressed as;
I = 1/3mr²
m is the mass of the body
r is the radius
Since there are three rotor blades, the moment of inertia will be;
I = 3(1/3mr²)
I = mr²
Given
m = 120kg
r = 3.50m
Required
Moment of inertia
Substitute the given values and get I
I = 120(3.50)²
I = 120(12.25)
I = 1470kgm²
Hence the moment of inertial of the three rotor blades about the axis of rotation is 1470kgm²
The physical model of the sun's interior has been confirmed by observations of neutrino and seismic vibrations.
<u>Explanation:</u>
Sun's interior is composed of very high temperature and solar flares. So it is very difficult to understand the interior of the sun. But by using the vibrations of neutrino and seismic waves emitted by the solar waves, the physical model can be assumed.
As the interior of the sun performs continuous chain of hydrogen cycle. So the continuous emission of energy from the chain reaction releases neutrino. So these vibrations in neutrino and seismic vibrations, the physical model can be assumed easily.
