Taking into account the rule of three for the change of units, the mass of the book is 45600 miligrams.
First of all, the rule of three is a mathematical tool that helps you quickly solve proportionality problems.
Having three known values and one unknown, a proportional relationship is established between all of them in order to find the fourth term of the proportion.
If the relationship between the magnitudes is direct (when one magnitude increases, so does the other; or when one magnitude decreases, so does the other), the rule of three is applied as follows, where a, b and c are known values and x is the unknown to calculate:
a → b
c → x
So: 
Being 1 kg equivalent to 1000000 milligrams, In this case the rule of three is applied as follows: if 1 kg equals 1000000 milligrams, 4.56×10⁻² kg equals how many milligrams?
1 kg → 1000000 milligrams
4.56×10⁻² kg → x
So:

<u><em>x=45600 miligrams</em></u>
In summary, the mass of the book is 45600 miligrams.
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Answer:
False
Explanation:
It is a common misunderstanding that objects in space have no weight. If that were true, they would just float away from the Earth, the Sun and the other planets. Objects in low Earth orbit experience about 90% of the weight that they feel on the surface of the Earth.
Answer: the options to the questions are
a. 1.0 moles of N2
b.0.5 moles of New
c.0.2 moles of CO2
d.2 moles of He
Answer D
Explanation:
The average molecular speed v of gas is given by =√(8RT,/πM)
From the equation it can be seen that substance with lowest molar mass has the highest velocity has He is the answer