Answer:
σ =4.180×10^{-9} C/m^2
Explanation:
electric field due to non conducting sheet is

the force acting on the piece of Styrofoam
Eq= mg
⇒E= mg/q
now,

⇒

charge per unit area (in C/m2) on the plastic sheet σ =4.180×10^{-9} C/m^2
Answer:
the velocity of the point P located on the horizontal diameter of the wheel at t = 1.4 s is 
Explanation:
The free-body diagram below shows the interpretation of the question; from the diagram , the wheel that is rolling in a clockwise directio will have two velocities at point P;
- the peripheral velocity that is directed downward
along the y-axis
- the linear velocity
that is directed along the x-axis
Now;


Also,

where
(angular velocity) = 

∴ the velocity of the point P located on the horizontal diameter of the wheel at t = 1.4 s is 
As we know that acceleration is given as

here we know that



now we will have


so acceleration will be 3 m/s^2
Answer:
The intensity is 
Explanation:
From the question we are told that
The intensity of the unpolarized light is 
The angle between the ideal polarizing sheet is 
Generally the intensity of light emerging from the first polarizer is mathematically represented as

substituting values


Then the intensity of incident light emerging from the second polarizer is mathematically represented by Malus law as

substituting values
![I_2 = 2000 * [cos (24.58)]^2](https://tex.z-dn.net/?f=I_2%20%20%3D%202000%20%20%2A%20%5Bcos%20%2824.58%29%5D%5E2)

Answer:
D. 2
Explanation:
The skydiver will reach terminal velocity when gravity = air resistance. When this occurs, he/she will no longer accelerate and his/her speed will be constant.
Once the skydiver opens the parachute, his/her speed will decrease suddenly, and again the air resistance increases due to the parachute's large area. Eventually, gravity will equal air resistance again and terminal velocity will be reached for the second time.
Even though the speeds are different, the first terminal velocity is much higher than the second one, this question refers to how many times terminal velocity is reached, not how many times the skydiver accelerates.