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Home Minds On Static Electricity Mission SE9 Coulomb's Law Calculations Help Help 1

Mission SE9 Coulomb's Law Calculations

The Question

Two objects (X and Y) are placed a distance of 0.300 m from each other. The charge on X is 1.380 x 10-6C and the charge on Y is 2.480 x 10-6C. What is the value of the electrical force (in Newtons) between the two objects?

(Numbers are randomly selected and may differ from those listed above.)

Physics Rules

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

where k is the constant of proportionality known as the Coulomb's law constant. The value of k is 9.0x109N•m2/ C2.

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Game Plan

Coulomb's law equation (stated in the Know the Law section) can be used to calculate the electrical force between objects X and Y. Substitute known values of k, Q1 and Q2 (in units of Coulombs or C) and d (in units of meters or m) into the equation and solve for the electrical force.

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