they are called "cells"
hope this is the answer is what your looking for.
Answer:
The question is incomplete. However, I believe, it is asking for the acceleration of the elevator. This is 3.16 m/s².
Explanation:
By Hooke's law, 
F is the force on a spring, k is the spring constant and e is the extension or compression.
From the question,

This is the force on the mass suspended on the spring. Its acceleration, a, is given by



This acceleration is more than the acceleration due to gravity, g = 9.8 m/s². Hence the elevator must be moving up with an acceleration of
12.96 - 9.8 m/s² = 3.16 m/s²
Total internal reflection complete reflection of a ray of light within a medium such as water or glass from the surrounding surfaces back into the medium. The phenomenon occurs if the angle of incidence is greater than a certain limiting angle, called the critical angle.
Answer:
When you toss a rolled up sock across the room, it travels faster as it becomes round and has more weight added on it and this causes the sock to travel in the direction you wish and this gives you a high chance of the sock going straight into the laundry basket, no matter how far away you are.
On the other hand, throwing a sock without rolling it up will cause the sock to just flat down as you throw it. It will travel at a low speed because it has no weight on it since it is flat, and if you try to throw it, it will atleast land 21 cm away from you. About a 0% chance of it getting in the basket.
Hope this helped! =>
Scattering occurs when light changes direction after colliding with particles of matter.