Answer:
a. cosθ b. E.A
Explanation:
a.The electric flux, Φ passing through a given area is directly proportional to the number of electric field , E, the area it passes through A and the cosine of the angle between E and A. So, if we have a surface, S of surface area A and an area vector dA normal to the surface S and electric field lines of field strength E passing through it, the component of the electric field in the direction of the area vector produces the electric flux through the area. If θ the angle between the electric field E and the area vector dA is zero ,that is θ = 0, the flux through the area is maximum. If θ = 90 (perpendicular) the flux is zero. If θ = 180 the flux is negative. Also, as A or E increase or decrease, the electric flux increases or decreases respectively. From our trigonometric functions, we know that 0 ≤ cos θ ≤ 1 for 90 ≤ θ ≤ 0 and -1 ≤ cos θ ≤ 0 for 180 ≤ θ ≤ 90. Since these satisfy the limiting conditions for the values of our electric flux, then cos θ is the required trigonometric function. In the attachment, there is a graph which shows the relationship between electric flux and the angle between the electric field lines and the area. It is a cosine function
b. From above, we have established that our electric flux, Ф = EAcosθ. Since this is the expression for the dot product of two vectors E and A where E is the number of electric field lines passing through the surface and A is the area of the surface and θ the angle between them, we write the electric flux as Ф = E.A
Good. You can do some very interesting experiments with that equipment.
Answer: 81.619 kJ
Explanation:
Given
Mass of roller coaster is 
It reaches the steepest hill with speed of 
Hill to bottom is 51 m long with inclination of 
Height of the hill is 
Conserving energy to get kinetic energy at bottom
Energy at top=Energy at bottom

Answer:
The percentage of an iceberg submerged beneath the surface of the ocean = 89.67%
Explanation:
Let V be the total volume of the iceberg
Let x be the volume of iceberg submerged
According to Archimedes principle,
weight of the iceberg = weight of the water displaced (that is, weight of x volume of water)
Weight of the iceberg = mg= ρ(iceberg) × V × g
Weight of water displaced = ρ(fluid) × x × g
We then have
ρ(iceberg) × V × g = ρ(fluid) × x × g
(x/V) = ρ(iceberg) ÷ ρ(fluid) = 916.3 ÷ 1021.9 = 0.8967 = 89.67%
Hope this Helps!!!!