Para abrir una puerta se comprime un resorte y, por defecto de este, la puerta se cierra automáticamente. ¿Qué forma de energía
1 answer:
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Answer:
The correct answer is B
Explanation:
Let's calculate the electric field using Gauss's law, which states that the electric field flow is equal to the charge faced by the dielectric permittivity
Φ = ∫ E. dA =
/ ε₀
For this case we create a Gaussian surface that is a sphere. We can see that the two of the sphere and the field lines from the spherical shell grant in the direction whereby the scalar product is reduced to the ordinary product
∫ E dA = / ε₀
The area of a sphere is
A = 4π r²
E 4π r² = / ε₀
E = (1 /4πε₀ ) q / r²
Having the solution of the problem let's analyze the points:
A ) r = 3R / 4 = 0.75 R.
In this case there is no charge inside the Gaussian surface therefore the electric field is zero
E = 0
B) r = 5R / 4 = 1.25R
In this case the entire charge is inside the Gaussian surface, the field is
E = (1 /4πε₀ ) Q / (1.25R)²
E = (1 /4πε₀ ) Q / R2 1 / 1.56²
E₀ = (1 /4π ε₀ ) Q / R²
= Eo /1.56
²
= 0.41 Eo
C) r = 2R
All charge inside is inside the Gaussian surface
=(1 /4π ε₀
) Q 1/(2R)²
= (1 /4π ε₀
) q/R² 1/4
= Eo 1/4
= 0.25 Eo
D) False the field changes with distance
The correct answer is B
Answer:
The work done by non-conservative forces on the car from the top of the first hill to the top of the second hill is 6574.75 joules.
Explanation:
By Principle of Energy Conservation and Work-Energy Theorem we present the equations that describe the situation of the roller coaster car on each top of the hill. Let consider that bottom has a height of zero meters.
From top of the first hill to the bottom
(1)
From the bottom to the top of the second hill
(2)
Where:
- Mass of the roller coaster car, in kilograms.
- Speed of the roller coaster car at the bottom between the two hills, in meters per second.
- Gravitational acceleration, in meters per square second.
- Height of the first top of the hill with respect to the bottom, in meters.
- Work done by non-conservative forces on the car between the top of the first hill and the bottom, in joules.
- Speed of the roller coaster car at the top of the second hill, in meters per seconds.
- Height of the second top of the hill with respect to the bottom, in meters.
- Work done by non-conservative forces on the car bewteen the bottom between the two hills and the top of the second hill, in joules.
By using (1) and (2), we reduce the system of equation into a sole expression:
(3)
Where is the work done by non-conservative forces on the car from the top of the first hill to the top of the second hill, in joules.
If we know that ,
,
,
and
, then the work done by non-conservative force is:
The work done by non-conservative forces on the car from the top of the first hill to the top of the second hill is 6574.75 joules.