Answer:

Explanation:
The electric flux is defined as the multiple of electric field and the area that the electric field passes through, such that

When calculating the electric flux, the angle between the directions of electric field and the area becomes important, especially if the angle is changing with time.
The above formula can be rewritten as follows

where θ is the angle between the electric field and the area of the loop. Note that, the direction of the area of the loop is perpendicular to the plane of the loop.
If the loop is rotating with constant angular velocity ω, then the angle can be written as follows

At t = 0, cos(0) = 1 and the electric flux through the loop is at its maximum value.
Therefore the electric flux can be written as a function of time

Answer:
J = 1800 kg-m/s
Explanation:
Given that,
Mass of a boy, m = 150 kg
Initial velocity of a boy, u = 12 m/s
Finally, it stops, v = 0
We need to find the impulse is required to produce this change in momentum. We know that impulse is equal to the change in momentum. So,

So, the impulse is equal to 1800 kg-m/s
Answer
given,
given,
small cube side = 10 cm
larger cube side = 12 cm
density of steel = 7 g/cm³
density of aluminium = 2.7 g/cm³
density of the water (ρ₁)= 1 g/cm³
Cube A and B made of steel
buoyant force of Cube A
B₁ = ρ₁ V g = 1 x 10 x 10 x 10 x g= 1000 g
for cube B
B₂ = ρ₁ V g = 1 x 12 x 12 x 12 x g= 1728 g
buoyant force of Cube C
B₃ = ρ₁ V g = 1 x 10 x 10 x 10 x g= 1000 g
for cube D
B₄ = ρ₁ V g = 1 x 12 x 12 x 12 x g= 1728 g
buoyant force acting on the cube depends on the density of the fluid
hence,
B₂ = B₄ > B₁ = B₃
we know
T=2.pie sqr root(l/g)
l= (sqrof 7/22)*9.8
L= .99 or approx 1m
As we know that friction force on box is given by

here we know that

here we have
m = 12 kg

so now we have

now we will have


so it required minimum 49 N(approx) force to move the block