Answer:
Radiation
Explanation:
The sun radiates energy to the earth to make it warmer near the equator.
Helpful friction would be the friction on something that you wanted to stop (a car) while unhelpful friction is friction on something that you want to keep going (a curling rock)
Answer: g= 9,81 m/s^2 ( average value for g in the Earth)
Explanation: The value of g depend on the localization on the Earth for example at the poles g is equal to: 9.83 m/s^2
On the other hand, at the aquator g=9.78 m/s^2
Answer:
Stars that have lower apparent magnitudes have more brightness.
Explanation:
Greek astronomer Hipparchus devised a system of arranging the luminosity of stars with their apparent magnitude. The brightest stars were in the first magnitude class, and the dimmer stars were in the latter magnitude classes.
Later in the 19th century technology had developed to accurately measure a star's brightness. It was established that a factor of exactly 100 times in intensity was due to difference of 5 magnitudes.
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