Question

1. Describe a scenario where two objects are electrically attracted to one another, but one of the objects is neutral in charge

2. What would happen if the force of gravity was stronger than the electrical force between two charges in space?

Answer 1

1.

A very good analogy is to consider magnetism, a close cousin of electricity.

If you have two North Poles and put them together they repel just as two positively charged objects would.

Similarly, If you have two South Poles and put them together they also repel just as two negatively charged objects would.

If you put the North pole next to a South Pole of a magnet they attract just as a positively and negatively charged object would.

If you take a piece of steel (with no overall magnetic field) and put it near a magnet it is also attracted, just as a neutral object would be attracted to a charged object.

Since "neutral" objects are made out of many positive and negative charges in equal measure, some of which can move, the presence of an electric field from a charged object will move these charges, and result in a region of opposite (to the object creating the field) charge where the neutral object is nearest to the charged object, and this will indeed result in an attraction between the formerly neutral object and the charged object.

Therefore, you cannot conclude from the attraction of two conducting objects that they must have the opposite charge - one of them may well be uncharged.

2.

Both gravitational and electric forces decrease with the square of the distance between the objects, and both forces act along a line between them. In Coulomb’s law, however, the magnitude and sign of the electric force are determined by the electric charge, rather than the mass, of an object. Thus, charge determines how electromagnetism influences the motion of charged objects. Charge is a basic property of matter. Every constituent of matter has an electric charge with a value that can be positive, negative, or zero. For example, electrons are negatively charged, and atomic nuclei are positively charged. Most bulk matter has an equal amount of positive and negative charge and thus has zero net charge.