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:
v = 6.79 m/s
Explanation:
It is given that,
Mass of a train car, m₁ = 11000 kg
Speed of train car, u₁ = 21 m/s
Mass of other train car, m₂ = 23000 kg
Initially, the other train car is at rest, u₂ = 0
It is a case based on inelastic collision as both car couples each other after the collision. The law of conservation of momentum satisied here. So,

V is the common velocity after the collisions

So, the two car train will move with a common velocity of 6.79 m/s.
U use the train to play hope i helped please thank me
Answer:
The length is d = 5
Explanation:
We must identify the respective coordinates of both points.
(x1,y1) = (2,3)
(x2,y2) = (5,7)
Now we know the distance equation of a straight line:

Answer:
Visible light when all put together is white. When objects appear to be, lets say, red, it would be the only color not absorbed by that object. same goes with all other colors. So black objects absorb all colors (not 100%) and that is why black clothing gets hotter, it simply absorbs all incoming light, as apposed to white that will reflect the colors back, making all of them together appear white. Hope this helps, not the best at explaining things.