Physics 9 worksheet: electric forces.
Work with your neighbor. Ask me for help if you’re stuck. Then we’ll discuss & check work all together.
Particles A, B, C carry identical positive charges qA=qB=qC= +10 µC=1.0×10−5C. Particle A
is located at (xA, yA) = (0,0) meters. Particle Bis at (xB, yB) = (+2.0,0.0) meters. Particle Cis at
(xC, yC) = (+1.0,+1.0) meters. The angles 6C AB and 6CBA are both 45◦. If you don’t have a calculator,
you can approximate k= 9 ×109N m2/C2≈1010 N m2/C2.
(1) What is the magnitude (in newtons) of the electric force between each pair of particles?
FE
AB =
FE
BA =
FE
AC =
FE
CA =
FE
BC =
FE
CB =
(2) Draw arrows for the two electric forces that are acting ON particle C. (The electric force exerted by
Aon Cis written ~
FE
AC . The electric force exerted by Bon Cis written ~
FE
BC .) Then draw an arrow for
the vector sum of forces (a.k.a. the “net force”) acting on particle C, which is written P~
FE
C. To make it
easier to compare results, choose the length of your arrows so that the grid size on your force diagram is
0.1 N. (Use the left grid below.)
