Addition of Vectors Review
|
Problem In class we have the three charges on the right and wanted to know what the net force is acting on charge 1. We first found the directions of the forces due to charges 2 and 3 separately, noting that like charges repel and unlike charges attract. The next step is to get the magnitudes. The final step is to do vector addition, which was covered earlier in the text. |
|
- First draw the forces due to the charge pairs.
|
F1 is the force due to charge 2 and F2 is that due to charge 3. The geometric sum of these forces is shown in the figure. |
|
- Next compute the magnitudes of each force.
- Now add
these. First you need the x and y components of each vector.
Then you can add them to get
and 
.
|
Vector |
x-component
(N) |
y-component
(N) |
|
F1 |
1.08 |
0 |
|
F2 |
|
|
|
F = F1+F2 |
-0.05 |
0.679 |
The sine and cosine of the angle between F2 and
the horizontal can be gotten from the big right triangle with sides 0.50 m,
0.30 m and hypotenuse 
m.
- Get Magnitude and Direction
We have that the components of the net force are Fx = -0.05 and Fy = 0.679. We can use these to get the magnitude and direction of the net force:
