A - opposite
I have to write 20 characters so....jghghgyf
If the object, ends up with a positive charge, then it is missing electrons. if it is missing electrons, then it must have been removed form the object during the rubbing process.
If you're referring to the different colors that usually occur at the tip of missles, rockets and some other aircraft, it either a) signifies the end of a particular plate of metal, fabricated specifically to be for the nose. Sometimes these can even be a different alloy or metal all together. or b) this shows where the curved surface begins, so in the case of damage or imperfections due to wear, they can be repaired and measured more easily. The shape of the nose is extremely important for smooth flight, and a dent or bump formed on it can make the aircraft unstable. If you can measure from where the curve starts by the difference in color, it makes repairing or re-fabricating the part much easier. Many of these curves aren't as simple as they appear.
When 2 electric charges are place close to each other they experience a force between them. This force may be repulsive or attractive depending on the type of charges involved.
The magnitude of this force depend on the quantity of individual charges and the distance between them.
The force is defined by the <em>Coulomb's law</em> states that: <em>The magnitude of the electrostatic force of attraction or repulsion between two point charges is directly proportional to the product of the magnitudes of charges and inversely proportional to the square of the distance between them.</em>
The formula for calculating the force between 2 electric charges is ;
F = (kq₁q₂)/d²
Where k is the proportionality constant known as Coulomb's constant,
q₁ and q₂ are the charges and
d is the distance between q₁ and q₂.