 # Coulombs Law p 538 in your book Two

• Slides: 13 Coulomb’s Law p. 538 in your book • Two electrically charged objects exert a force on each other. • Opposite charges ATTRACT • Notice the forces are “equal but opposite” Charged objects & electrical force • Two electrically charged objects exert a force on each other. • Like charges REPEL • Notice the forces are “equal but opposite” Charged objects & electrical force • Coulomb’s Law • Coulomb’s Law • Two objects, whose charges are +1. 0 C and 1. 0 C are separated by 1. 0 km. Find the magnitude of the attractive force that either charge exerts on the other. • F = 9. 0 x 103 N Example 1 p. 539 • Similarities: Both are inverse square laws The force is directed along a line between the two objects Difference: Electrostatic force can be either attractive or repulsive Gravitational force is always attractive Notice anything familiar? • Notice anything familiar? • We can use Coulomb’s law to determine the net electrostatic force acting on a point charge (q 1) due to multiple other point charges (q 2 and q 3). More than 2 point charges • First determine the force (magnitude and direction!) that q 3 exerts on q 1 (ignore q 2) • Then determine the force (magnitude and direction!) that q 2 exerts on q 1 (ignore q 3) More than 2 point charges • The net force on q 1 is the vector sum of these two forces. More than 2 point charges • Determine the magnitude and direction of the net electrostatic force on q 1. • +5. 7 N Example 4 p. 541 • Coulomb’s law worksheet Assignment