Answer:

Solution:
As per the question:
Point charge, q = 
Test charge, 
Work done by the electric force, 
Now,
We know that the electric potential at a point is given by:

where
r = separation distance between the charges.
Also,
The work done by the electric force i moving a test charge from point A to B in an electric field:




Answer:
Explanation:you must first make a free body diagram of the block to place all the forces that act on the block there. You will have four forces. The normal force, the weight, the horizontal force in x (which is what they ask to calculate) and the friction force. Then you raise the equations and you clear the values. I attach the solution.
Any object that is spherical in shape would best represent a true scale model of the shape of the Earth. Examples are ping pong balls, billiard balls, marble and other smooth spherical objects. The shape of the Earth is called the oblate spheroid. The "oblate" would refer to an oblong shape and "spheroid" would refer to an almost spherical shape. The earth has on almost spherical shape and has a slightly oblong appearance. The diameter from the South pole to the north pole was measured to have a value of 12714 km while the diameter of the equator is approximately 12756 km. As you can see, the values are not equal. This makes the earth not a perfect sphere.
low density, malleable, easy to form into shapes, not very chem reactive