Answer:
Explanation:
Total internal reflections is a phenomenon where incident light rays when travelling from a denser medium or from a medium with higher refractive index to less dense medium or a medium with lesser refractive index ( The indices of refraction have the relation n₁ > n₂, where n₁ is the refractive index of the first medium and n₂ is the refractive index of medium 2) leads to the light ray being reflected back into the first medium instead of undergoing refraction. Usually, this occurs when the incident light rays angle to the normal is greater than a certain critical angle which is the angle when the refracted ray angle in the second medium is 90°
It's C i believe. To solve it we just take 20 and divide it by 2. Which gives us the average of 10 m/s
-Steel jelly
The force between the two objects is 19.73 nN.
<u>Explanation:
</u>
Any force acting between two objects tends to be directly proportional to the product of their masses and inversely proportional to the square of the distance between the two objects. And this kind of attraction force between two objects is termed as gravitational force.
So if we consider
and
as the masses of both objects and let d be the distance of separation of two objects. Then the force between the two objects can be determined as below:

As gravitational constant
,
= 20 kg and
= 100 kg, while d = 2.6 m, then

Thus, we get finally,

As we know, nano denoted by letter 'n' equals to 
So the force acting between two objects is 19.73 nN.