C is the answer to your question.
So E = 2x10^-3W/m^2*(π*(3.0x10^-3m)^2)*1min*60s... = 3.4x10^-6J
Answer:
E=3 x 10^4 N/c
Explanation:
The electric field strength can be found out disk with a uniform positive surface charge density by

σ= charge density
r= radius of the disk
z= position in which we have to find electric field = 15 cm
ε_0= constant ( vacuum permitivity)
putting values we get

solving we get
E=30000 N/c
E=3 x 10^4 N/c
Answer:
9.8 × 10⁴Pa
Explanation:
Given:
Velocity V₁ = 12m/s
Pressure P₁ = 3 × 10⁴ Pa
From continuity equation we have
ρA₁V₁ = ρA₂V₂
A₁V₁ = A₂V₂
making V₂ the subject of the equation;

the pipe is widened to twice its original radius,
r₂ = 2r₁
then the cross-sectional area A₂ = 4A₁
⇒ 

This implies that the water speed will drop by a factor of
because of the increase the pipe cross-sectional area.
The Bernoulli Equation;
Energy per unit volume before = Energy per unit volume after
p₁ +
ρV₁² + ρgh₁ = p₂ +
ρV₂² + ρgh₂
Total pressure is constant and
= P =
ρV₂²ρV²
p₁ +
ρV₁² = p₂ +
ρV₂²
Making p₂ the subject of the equation above;
p₂ = p₁ +
ρV₁² -
ρV₂²
But
so,
p₂ = p₁ +
ρV₁² -
ρ
p₂ = 3.0 x 10⁴ + (
× 1000 × 12²) - (
× 1000 × 12²/4² )
P₂ = 3.0 x 10⁴ + 7.2 × 10⁴ - 4.05 x 10³
P₂ = 9.79 × 10⁴Pa
P₂ = 9.8 × 10⁴Pa
Answer:106560 N
Explanation:
Given
Let Tension between 2 and 3 car be
and between 3 &4 is 

mass of freight car =37,000 kg
acceleration of car
is accelerating all freights behind 3
therefore


Thus

