I attached the full question.
We know that for a parallel-plate capacitor the surface charge density is given by the following formula:

Where V is the voltage between the plates and d is separation.
Voltage is by definition:

Voltage is analog to the mechanical work done by the force.
Above formula is correct only If the field is constant, and we can assume that it is since no function has been given.
The charge density would then be:

Please note that elecric permittivity of air is very close to elecric permittivity of vacum, it is common to use them <span>interchangeably</span>.
Increase in sea water pollution
electromagnet
When a electric current is passed through an insulated wire that is coiled around an iron core, like a nail, an electromagnet is created.
The final momentum of the ball is 3.8 kgm/s.
<h3>Change in momentum of the ball</h3>
The impulse received by the ball is equal to change in momentum of the ball.
J = ΔP
where;
- J is the impulse
- ΔP is change in momentum
ΔP = P₂ - P₁
P₂ = ΔP + P₁
<h3>Final momentum of the ball</h3>
The final momentum of the ball is calculated as follows;
P₂ = 8 + (- 0.1 x 42)
P₂ = 8 - 4.2
P₂ = 3.8 kgm/s
Learn more about change in momentum here: brainly.com/question/7538238
Speed can be thought of as the rate at which an object covers distance. ... Speed has the dimensions of distance divided by time. The SI unit of speed is the metre per second, but the most common unit of speed in everyday usage is the kilometre per hour or, in the US and the UK, miles per hour........?