Your 'torques' report 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: **
B = .9 cm, A = 7.3 cm, C = 10.5 cm
7.9 cm, 10 cm, 9.7 cm
1.3 N, 2.5 N, 2.4N
The measurements were taken from the far left of the rod.
I got these results by extending my rubberband calibration graphs for each of the distances of the rubberbands and found the corresponding force that applied from the graph.
THe first line is the distance from the left hand side of the rod of the spacing between the rubber bands. The second line is the length of each rubberband. The third line is the force of each rubberband corresponding to my graphs on the calibration experiment.
** Net force and net force as a percent of the sum of the magnitudes of all forces: **
-1.2
19%
I added the all of the forces to get the net force. Force A was positive at 2.5N, force B was negative at -1.3N, force C was negative at -2.4N. The total was -1.2N. The sum of all the forces I took to make them all in the positive direction. The sume was 6.2N. The percent of the net to the sum is 1.2/6.2 = 19%.
** Moment arms for rubber band systems B and C **
6.4 cm, 3.2 cm
I got these lines by measuring the distance from the fulcrum to each of the points where the hook was attached to the rubberband.
** Lengths in cm of force vectors in 4 cm to 1 N scale drawing, distances from the fulcrum to points B and C. **
5.2cm, 10 cm, 9.6 cm
6.2 cm, 3.2 cm
The first line I got by doing a ration of 4 cm to 1 Newton for each of my forces. For example, for a force of 2.5 N that would be a length of 10 cm. The numbers in the second line are the distances from the fulcrum to each of the rubberbands, b and c.
** Torque produced by B, torque produced by C: **
+8.32, -7.68
These are the 2 torques for B and C respectively.
I got these by multiplying the moment arm by the force of each rubber band. For example, for rubberband B, I multiplied 6.4 cm * 1.3N = 8.32. Since this will be in the counterclockwise direction, it should be positive.
** Net torque, net torque as percent of the sum of the magnitudes of the torques: **
Net torque = .64
4%
I got the first line by adding -7.68 + 8.32 to get .64. The sum of these 2 torques without the positive or negative signs is 16. I got the percent by dividing .64/16.
** Forces, distances from equilibrium and torques exerted by A, B, C, D: **
** 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: **
** Net torque for given picture; your discussion of whether this figure could be accurate for a stationary rod: **
** 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: **
** 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: **
&#Very good work. Let me know if you have questions. &#