The Earth's gravitational pull and the table's force are of equal magnitude and in opposite directions, they balance each other.
<u>Explanation:</u>
A book placed on a surface have two forces acting on it which are, a force that pulls it toward the ground in a downward direction, that is gravitational pull and a second which is acted on the book on upward direction making a balance on the object.
This follows Newton’s third law of motion that states every action has an equal and opposite reaction. 
Recall that
where 
and 
are the initial and final velocities, respecitvely; 
is the acceleration; and 
is the change in position.
So we have
(Normally, this equation has two solutions, but we omit the negative one because the car is moving in one direction.)
<em>Newton's second law of motion can be formally stated as follows: The acceleration of an object as produced by a net force is directly proportional to the magnitude of the net force, in the same direction as the net force, and inversely proportional to the mass of the object.</em>
When a beam of light is traveling through air and is reflected by a glass surface, then the 2R / (1+R) is the total reflectance through a glass window.
To find the answer, we have to know about reflection.
<h3>
What is reflection by glass surface?</h3>
- Depending on the angle of incidence, the refractive indices of the glass and the light's source, some light is reflected when it strikes a glass surface (e.g., air).
- The Fresnel equations can be used to calculate the percentage of transmitted and reflected light.
- Both the front and the rear of glass reflect the light that is traveling through it. In fact, the light may mirror itself several times. Therefore, 2R / (1+R) is the total reflectance through a glass window.
- These equations predict that ordinary soda-lime window glass will reflect around 8% of the light, assuming a perpendicular incidence angle and no absorption or scattering.
Thus, we can conclude that, when a beam of light is traveling through air and is reflected by a glass surface, then the 2R / (1+R) is the total reflectance through a glass window.
Learn more about the reflection here:
brainly.com/question/5012638
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Exothermic is the right kind of reaction.
