16-6 Solving Problems with Coulomb’s Law and Vectors

•Electrostatic force, or Coulomb’s force is the force between 2 or more charged particles, at rest.

•Charges are considered to be point charges.

•The study of these forces and charges is called electrostatics.

•Solutions for forces can be made graphically or by use of trig functions and the Pythagorean theorem.

16-6 (Cont’d)

• See Example 16-3 and Example 16-4

16-7 Electric Field

• The idea of electric field was proposed first by Michael Faraday (1791-1867)

• Electric field is the field of force exerted on a tiny positive test charge at its location.

• E=F/q

• So… E=(kqQ/r2)/q= kQ/r2

• F=[1/(4o)] (Q/r2)

o=1/4k= 8.85x10-12C2/N.m2

16-7 Cont’d

• See Example 16-5 and 16-6 p487

• See Example 16-7 and 16-8 p488/489

16-8 Field Lines

• Electric field lines or lines of force, are drawn to indicate the force on a positive test charge.

• The lines point away from plus and to minus.• The number of lines are proportional to the

charge.• Lines run from plus to minus until they are

neutral.• See page 490 and 491• The field concept can also be applied to gravity.

HOMEWORK• P498 PR21-29 and pr# 34 and question

16 and 19 due Thurs. BOP