Answer:
Please see below as the answers are self-explanatory.
Explanation:
1) The resultant force is along the line that joins both charges or both masses (assuming both objects can be represented as points)
2) Both type of forces obey Newton's 3rd law.
3) Both are proportional to the product of the property that is affected by the force (charges and masses)
4) Both obey an inverse - square law (consequence of our universe being three-dimensional)
1) Main difference, is that while the gravitational force is always attractive, the electrostatic force can be attractive or repulsive, as there are two types of charges, which attract each other being of different type, and repel each other if they are of the same type.
2) It is possible, artificially, to block the influence of the electrostatic force, shielding a room, for instance, which is not possible for the gravitational force.
Answer:
The correct option is (b).
Explanation:
Given that,
Electric field, 
We need to find the magnitude of the force on the electron as a result of the electric field.
We know that, the electric force is given by :

So, the required force on the electron is equal to
.
Answer:
The time for the cake to cool off to room temperature is
approximately 30 minutes.
Let
=
F be the temperature and T that of the body
Explanation:
Our Tm = 70, the initial-value problem is
= <em>k</em>(T − 70), T(0) = 300
Solving the equation, we get
= <em>kdt</em>
In [T-70]= <em>kt </em>+
T = 70 +

Finding he value for
using the initial value of T (0)= 300, therefore we get:
300=70+
= 230 therefore
T= 70+ 230 
Finding the value for <em>k </em>using T (3) = 200, therefore we get
T (3) = 200
= 
<em>K </em>=
in 
= -0.19018
Therefore
T(t) = 70+230
<span>Δ</span>E = q + w
q = heat (quantity of)
q and w can be positive or negative depending on if work/heat is being absorbed/done on the system or released/done by the system
The expression of the electric flux is

Here,
Q = Total charge enclosed in the closed surface
= Permittivity due to free space
Rearranging to find the charge,

Replacing with our values we have finally



The charge enclosed by the box is 0.1684nC
The sign of the charge can be decided by using the direction of the flux. The charge enclosed by the cube can be calculated by using the electric flux and the permitivity of free space.