Answer:

Explanation:
From the question we are told that:
Length 
Distance apart 
Electron Transferred 
Therefore
Total Charge
Since Charge on each electron is

Therefore


Generally the equation for Charge density is mathematically given by

Where
Area


Therefore


Generally the equation for Electric Field in the capacitor is mathematically given by



Answer:
Second ball
Explanation:
When a ball is thrown up with a certain velocity when the object reaches the same point from where it was thrown the velocity of the object becomes equal to the velocity with which the ball was thrown.
First ball

Second ball

Third ball

From the equations above it can be seen that the second ball will have the highest velocity when it hits the ground.
So, 
Answer:
a = 6.7 m/s²
Explanation:
The formula to apply here is :
Mass * acceleration = Tension -weight
m*a = Ft -mg -----where m is mass of block, a is acceleration , Ft is force due to tension.
Given in the question that ;
Mass of block = 3 kg
Ft = 50 N
g= 10
m*a = Ft -mg
3*a = 50-30
3a= 20
a= 20/3
a= 6.7 m/s²