Answer:
(A) 60 J
Explanation:
At state 1
KE₁=100 J
At state 2
KE₂ = 0
U₂=80 J
Given that surface is rough so friction force will act in opposite to the direction of motion
Lets take work done by friction = Wfr
From work power energy
Work done by all forces = Change in kinetic energy
Wfr + U₂=ΔKE
Wfr+80 = 100
Wfr= 20 J
Now when book slides from top position then
Wfr+ U = KEf - KEi
-20 + 80 = KEf-0
KEf= 60 J
(A) 60 J
Primary Waves
Secondary go only through air, but not water.
No not all, because not all electrical field attract and repel
Pegasus<span>, considering the fact that </span>unicorns<span> were, and still are, real. </span>
Answer:
E = 
Explanation:
For this exercise we use that the electric field is a vector, so the resulting field is
E_total = E₁ + E₂ (1)
since the field has the same direction in the space between the planes
Let's use Gauss's law for the electric field of each plate
Let's use a Gaussian surface that is a cylinder with the base parallel to the plate, therefore the normal to the surface and the field lines are parallel and the angle is zero so cos 0 = 1
Ф = ∫ .dA =
/ε₀
if we assume that the charge is uniformly distributed on the plate we can define a charge density
σ = q_{int} A
as the field exists on both sides of the plate on the inside
E A = A σ / 2ε₀
E = σ / 2ε₀
we substitute in equation 1
E = σ /ε₀
for the complete plate
σ = Q / A = Q / L²
we substitute
E = 