Static Electricity - Mission SE8 Detailed Help


The electrical force between two objects is 36 N. If the charge on one of the objects is doubled AND the distance between them is doubled, the force between them will be ___.


 
Coulomb's Law of Electrical Interaction:
The electrical force exerted between two charged objects is directly proportional to the product of the quantity of charge on the objects (Q1 and Q2) and inversely proportional to the square of the separation distance (d) between the two objects. In equation form,
 
Felect= k • Q1• Q2/ d2

k is the constant of proportionality known as the Coulomb's law constant.


 
This is a question in which you must predict the value of the new force which results from an alteration in both the quantity of charge and the separation distance. Coulomb's law states the dependence of force on both the quantity of charge and the separation distance. The best approach to this question involves changing the 36 N force in two steps - once for the alteration in the quantity of charge and then again for the alteration in the separation distance. The Math Magic section describes how these two variables affect the electrical force.


 
Coulomb's law states the relationship between electrical force of interaction between two objects and the quantity of charge present on the objects. See Know the Law section. The force of attraction or repulsion shows a direct dependence upon the product of the quantity of charge on the two objects. If the quantity of charge on either one of the objects is increased, then the force will be increased. And by whatever factor the quantity of charge is increased, the force is increased by that same factor. If the quantity of charge is made four times bigger, the force will be four times bigger.
 
Coulomb's law states the relationship between electrical force of attraction between two objects and the distance of separation between the objects. See Know the Law section. The relationship between force and distance is often referred to as an inverse square law relationship. The force is inversely proportional to the square of the distance. If the distance is increased - doubled or tripled - then the force will be decreased or made smaller. If the distance is decreased - halved - then the force will be increased or made larger. And by whatever factor the distance is changed, the force will change in the inverse direction by the square of that factor. So if the distance is made four times bigger, the force will be 16 (4 squared) times smaller. So if the original force value is known, the new force value could be found by dividing the original value by 16. And if the distance is made five times smaller, the force will be made 25 (5 squared) times larger. So if the original force value is known, the new force value could be found by multiplying the original value by 25.