"When we do experiments it's a good idea to do multiple trials, that is, do the same experiment lots of times. When we do multiple trials of the same experiment, we can make sure that our results are consistent and not altered by random events. Multiple trials can be done at one time."
Answer:
B. It is directly proportional to the source charge.
Explanation:
Gauss's law states that the total (net) flux of an electric field at points on a closed surface is directly proportional to the electric charge enclosed by that surface.
This ultimately implies that, Gauss's law relates the electric field at points on a closed surface to the net charge enclosed by that surface.
This electromagnetism law was formulated in 1835 by famous scientists known as Carl Friedrich Gauss.
Mathematically, Gauss's law is given by this formula;
ϕ = (Q/ϵ0)
Where;
ϕ is the electric flux.
Q represents the total charge in an enclosed surface.
ε0 is the electric constant.
Hence, the statement which is true of the electric field at a distance from the source charge is that it is directly proportional to the source charge.
Solution :
Given :
Rectangular wingspan
Length,L = 17.5 m
Chord, c = 3 m
Free stream velocity of flow, 
= 200 m/s
Given that the flow is laminar.
So boundary layer thickness,
= 0.0024 m
The dynamic pressure, 
The skin friction drag co-efficient is given by
= 0.00021
= 270 N
Therefore the net drag = 270 x 2
= 540 N
