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: **
.5cm, 8cm, 12.1cm
8.2cm, 8.3cm, 8.67cm
1.21N, 2.83N, 1.9N
The reference point was the end of the all-thread.
To get force from my calibration graphs I started at the length along the x axis the moved up to the curve and then where I met the curve over to the y axis and the corresponding force.
The first line are the lengths from the reference point that the vertical lines crossed the horizontal line.
The second line is the lengths I measured of rubber bands B,A, and C.
The third is the forces of the rubberbands at that length that I described how to get in line 5, to get the force of the double rubber band (A) I got the force for each individual rubber band at that length then added them together.
** Net force and net force as a percent of the sum of the magnitudes of all forces: **
-.28N
5%
The first line is the net force of the system 2.83N-1.21N-1.9N= -.28N.
The second line is the what percentage the net force is of the sum of all magnitudes. .28N/(2.83N+1.21N+1.9N)= .28N/5.94N= .05*100%= 5%
** Moment arms for rubber band systems B and C **
7.5cm, 4.1cm
The first distance is the distance I measured from the point where rubber band B crossed the horizontal to the fulcrum. The second distance is the distance I measured from the point where rubber band C crossed the horizontal to the fulcrum.
** Lengths in cm of force vectors in 4 cm to 1 N scale drawing, distances from the fulcrum to points B and C. **
4.84cm, 11.32cm, 7.6cm
7.5cm, 4.1cm
The first line is the length of the vectors drawn to a scale of 1N to 4cm.
For the second line the first distance is the distance I measured from the point where rubber band B crossed the horizontal to the fulcrum. The second distance is the distance I measured from the point where rubber band C crossed the horizontal to the fulcrum.
** Torque produced by B, torque produced by C: **
-.46N/cm, .16N/cm
The first number is the torque of the force exerted by rubber band C about the point of suspension I got it by dividing the force the rubber band exerted by the length of the moment arm 1.9N/4.1cm= .46N/cm it is negative because it is producing a clockwise torque. The second number is the torque of the force exerted by rubber band B about the point of suspension I got it by dividing the force the rubber band exerted by the length of the moment arm 1.21N/7.5cm= .16N/cm it is positive because it is producing a counter-clockwise torque.
To get torque you multiply moment arm by force. The units are cm * N.
** Net torque, net torque as percent of the sum of the magnitudes of the torques: **
-.3N/cm
50%
To get The net torque I added both torques -.46N/cm+.16N/cm= -.3N/cm. To get this as a percentage of the sum of the torques I added the torques .46N/cm+.16N/cm= .62N/cm Then divided the net torque by the sum and multiplied by %100 .3N/cm /.62N/cm= .5*%100= %5
** 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? **
2hrs
** Optional additional comments and/or questions: **
Everything looks good except for your calculation of the torques. Please submit a revision with those calculations corrected. Just submit a copy of this document and indicate your revised results with &&&&.