Line of Action
Is a line parallel to and in line with the force. The force may be considered as acting anywhere along its line of action.
one force that will produce the same effect on a body as two or more other forces. If the forces have the same line of action, they may be added directly for the resultant.
What do you need to keep in mind when determining resultants?
1. Order of drawing forces makes no difference.
2. Resultant is directed "away" from the origin or starting point.
3. The resultant is concurrent with the original forces. (their lines of action pass through a common point.)
Replacing one force with two or more forces that will produce the same effect on a body as the original force. These forces are called components.
Right Triangle Formulas
1. Sin Theta = A/C
2. Cos Theta = B/C
3. Tan Theta = A/B
4. A = C sin theta
5. B = C cos theta
6. CC = the square root of AA + B*B
these basic rules may easily be used to determine the vertical and horizontal components of a force.