To develop this problem we will apply the concepts related to the potential energy per unit volume for which we will obtain an energy density relationship that can be related to the electric field. From this formula it will be possible to find the electric field required in the problem. Our values are given as
The potential energy, 
The volume, 
The potential energy per unit volume is defined as the energy density.



The energy density related with electric field is given by

Here, the permitivity of the free space is

Therefore, rerranging to find the electric field strength we have,



Therefore the electric field is 2.21V/m
Answer:
W = 1884J
Explanation:
This question is incomplete. The original question was:
<em>Consider a motor that exerts a constant torque of 25.0 N.m to a horizontal platform whose moment of inertia is 50.0kg.m^2 . Assume that the platform is initially at rest and the torque is applied for 12.0rotations . Neglect friction.
</em>
<em>
How much work W does the motor do on the platform during this process? Enter your answer in joules to four significant figures.</em>
The amount of work done by the motor is given by:


Where I = 50kg.m^2 and ωo = rad/s. We need to calculate ωf.
By using kinematics:

But we don't have the acceleration yet. So, we have to calculate it by making a sum of torque:

=> 
Now we can calculate the final velocity:

Finally, we calculate the total work:

Since the question asked to "<em>Enter your answer in joules to four significant figures.</em>":
W = 1884J
Answer:
The temperature is 
Explanation:
From the question ewe are told that
The rate of heat transferred is 
The surface area is 
The emissivity of its surface is 
Generally, the rate of heat transfer is mathematically represented as

=> ![T = \sqrt[4]{\frac{P}{e* \sigma } }](https://tex.z-dn.net/?f=T%20%20%3D%20%20%5Csqrt%5B4%5D%7B%5Cfrac%7BP%7D%7Be%2A%20%5Csigma%20%7D%20%7D)
where
is the Boltzmann constant with value 
substituting value
![T = \sqrt[4]{\frac{13.1}{ 0.287* 5.67 *10^{-8} } }](https://tex.z-dn.net/?f=T%20%20%3D%20%20%5Csqrt%5B4%5D%7B%5Cfrac%7B13.1%7D%7B%200.287%2A%205.67%20%2A10%5E%7B-8%7D%20%7D%20%7D)

Answer:
Vb = k Q / r r <R
Vb = k q / R³ (R² - r²) r >R
Explanation:
The electic potential is defined by
ΔV = - ∫ E .ds
We calculate the potential in the line of the electric pipe, therefore the scalar product reduces the algebraic product
VB - VA = - ∫ E dr
Let's substitute every equation they give us and we find out
r> R
Va = - ∫ (k Q / r²) dr
-Va = - k Q (- 1 / r)
We evaluate with it Va = 0 for r = infinity
Vb = k Q / r r <R
We perform the calculation of the power with the expression of the electric field that they give us
Vb = - int (kQ / R3 r) dr
We integrate and evaluate from the starting point r = R to the final point r <R
Vb = ∫kq / R³ r dr
Vb = k q / R³ (R² - r²)
This is the electric field in the whole space, the places of interest are r = 0, r = R and r = infinity