Answer:
finding Cepheid variable and measuring their periods.
Explanation:
This method is called finding Cepheid variable and measuring their periods.
Cepheid variable is actually a type of star that has a radial pulsation having a varying brightness and diameter. This change in brightness is very well defined having a period and amplitude.
A potent clear link between the luminosity and pulsation period of a Cepheid variable developed Cepheids as an important determinants of cosmic criteria for scaling galactic and extra galactic distances. Henrietta Swan Leavitt revealed this robust feature of conventional Cepheid in 1908 after observing thousands of variable stars in the Magellanic Clouds. This in fact turn, by making comparisons its established luminosity to its measured brightness, allows one to evaluate the distance to the star.
Answer:
4.1 m
Explanation:
10 kW = 10000 W
20mi/h = 20*1.6 km/mi = 32 km/h = 32 * 1000 (m/km) *(1/3600) hr/s = 8.89 m/s
The power yielded by the wind turbine can be calculated using the following formula
where is the air density, v = 8.89 m/s is the wind speed, A is the swept area and is the efficiency
The swept area is a circle with radius r being the blade length
Sound waves are longitudal waves meaning they go back and forth
Answer : Radius of Earth is 6,340 Km.
Explanation
It is given that,
Tangential velocity of Earth at the equator, v = 465 m/s
Centripetal acceleration at the equation is,
We know that the relation between centripetal acceleration and tangential velocity is :
..........(1)
Where,
v is tangential velocity
r is the radius
Putting all values in equation (1)
or
The Earth's radius is 6,340 Km. Hence, this is the required solution.
First you have to note down you horoscope for 2-3 days.
Daily observe what is written in your horoscope is true or not. You can observe your entire day movements.
Now you have to conclude whether your horoscope was true or not and you have to write an essay explaining what had happened to you in past observation and conclude whether you believe in astronomy or not depending on your observations