Your work on torques has been received. Scroll down through the document to see any comments I might have inserted, and my final comment at the end.
Your optional message or comment:
Positions of the three points of application, lengths of systems B, A and C (left to right), the forces in Newtons exerted by those systems, description of the reference point:
.5cm, 7cm, 12.2cm
8.3cm, 8.3cm, 8.2cm
1.9N, 3.7N, 2.0N
The positions were measured relative to the left of the rod. I found the force according to my best fit line that corresponded to each length for the specific rubber bands used.
Net force and net force as a percent of the sum of the magnitudes of all forces:
-.2N
2.5%
Moment arms for rubber band systems B and C
6.5, 5.2
Lengths in cm of force vectors in 4 cm to 1 N scale drawing, distances from the fulcrum to points B and C.
7.6, 7.6, 14.8
6.5, 5.2
Torque produced by B, torque produced by C:
+12.4, -10.4
Net torque, net torque as percent of the sum of the magnitudes of the torques:
2.0
9%
Forces, distances from equilibrium and torques exerted by A, B, C, D:
1.8, 1.65, 1.3, .7
5.9, 5.0, 4.8, 7.5
+10.6, -8.3, -6.2, +5.25
The distances of A, B, C and D from equilibrium, which is taken to be the point of action of the leftmost force A, would be increasing as you move from left to right. You might have been reporting the distances between the points, rather than the distances from the single fixed point of reference. This will affect your results for the torques.
The sum of the vertical forces on the rod, and your discussion of the extent to which your picture fails to accurately describe the forces:
+1.35
My picture does fail to accurately depict the forces acting on the rod. The sum of all torques should have been zero.
Net torque for given picture; your discussion of whether this figure could be accurate for a stationary rod:
No, it is not completely accurate. The sum of all torques should have been zero.
For first setup: Sum of torques for your setup; magnitude of resultant and sum of magnitudes of forces; magnitude of resultant as percent of sum of magnitudes of forces; magnitude of resultant torque, sum of magnitudes of torques, magnitude of resultant torque as percent of the sum of the magnitudes:
+10.6
1.8, 4.75
I am starting to get lost.
I believe that for the first setup you have all the necessary information up to this point (but note my previous comment about your reported positions for A, B, C and D), and should be able to answer these questions on the basis of that information. What specific questions are giving you trouble?
If the second setup is giving you trouble, please let me know what specific instructions are causing the difficulty.
For second setup: Sum of torques for your setup; magnitude of resultant and sum of magnitudes of forces; magnitude of resultant as percent of sum of magnitudes of forces; magnitude of resultant torque, sum of magnitudes of torques, magnitude of resultant torque as percent of the sum of the magnitudes:
In the second setup, were the forces all parallel to one another?
Estimated angles of the four forces; short discussion of accuracy of estimates.
x and y coordinates of both ends of each rubber band, in cm
Lengths and forces exerted systems B, A and C:.
Sines and cosines of systems B, A and C:
Magnitude, angle with horizontal and angle in the plane for each force:
x and y components of sketch, x and y components of force from sketch components, x and y components from magnitude, sine and cosine (lines in order B, A, C):
Sum of x components, ideal sum, how close are you to the ideal; then the same for y components.
Distance of the point of action from that of the leftmost force, component perpendicular to the rod, and torque for each force:
Sum of torques, ideal sum, how close are you to the ideal.
How long did it take you to complete this experiment?
Optional additional comments and/or questions:
See my note above and please respond as indicated.