The mass number of an element is equivalent to the number of Protons and Neutrons in the element. For example Oxygen has eight protons and neutrons, therefore its mass number is 16. You could also calculate this by simply rounding the atomic weight of the element to the nearest whole number. Oxygen's atomic weight is 15.994, which as you can see, would be rounded to 16 :)
Hello My Friend!<span>The </span>
Axis<span> of rotation is an imaginary line </span>
passing through the centre of mass of any celestial body around which the celestial body rotates.
So in Other Words, t<span>he </span>Earth<span> makes
one complete rotation around this imaginary </span>axis<span>
every 23 hours 56 minutes 4 seconds (Rounded up = 24 Hours).
</span>
Ps. <span>The line </span>
passes through<span> the
north and south poles of a planet.
</span>
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This is due to the amount of infrastructure in the city. All that metal holds heat making inside the city hotter than outside the city.
<span>Mercury's distance at inferior conjunction is 0.61 AU
Looking at a table of orbits, Mercury has an orbital distance of 0.39 AU. So the inferior conjunction will be:
1 AU - 0.39 AU = 0.61 AU</span>