Answer:
force becomes one - ninth
Explanation:
According to Coulomb's law in electrostatics, two charges can exert a force of attraction or repulsion on each other which is directly proportional to the product of two charges and inversely proportional to the square of distance between them.
Here both the charges remains same but the distance is variable.
So, we can say that
.... (1)
Where d be the distance between the tow charges
As the distance between two charges increases by factor of three, let the new force be F'.
.... (2)
Divide equation (2) by equation (1), we get


Thus, the force becomes one - ninth times the initial force.
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.
Learn more:
The speed of sound at T=25°C is Vs=346 m/s. So the sound has to reach the cliff and return back to you so the path it needs to travel is s=2*440 m = 880 m.
Since the speed of sound is constant s=Vs*t, and t= s/Vs=880/346=2.54335 s. You will hear the echo after t=2.54335 s after you shouted.
Answer:
Since the ball becomes positively charged, it will repel as like charges repel.
Answer:
When the velocity of an object changes it is said to be accelerating. Acceleration is the rate of change of velocity with time. ... Acceleration occurs anytime an object's speed increases or decreases, or it changes direction.