Given that a hot air balloon lifts 50 meters vertically into the air and then comes back down.
The displacement is the distance covered in a specific direction.
When the balloon is going up, the displacement is positive. and when the balloon is coming down, the displacement is negative.
The total displacement = 50 - 50 = 0
The distance is a measurement of length between to different points or position.
For distance, there is no need to consider direction. There is no consideration for positive or negative signs
While the distance = 50 + 50 = 100 meters
Therefore, the correct answer is C
That is, The displacement is zero and the distance is 100 meters
Learn more on ; brainly.com/question/24662122
Difference between solid friction and viscosity is as follows: Viscosity is proportional to the surface area whereas solid friction is independent of area of solid surfaces in contact. Viscous force on the body depends upon its velocity in the viscous media. But, friction does not depend on the velocity of the body.
The molarity remains the same so the ratio does not change
He preformed the first ever successful open heart surgery
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: