Phy 231
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: **
Part 1
** 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: **
0, 7, 14
7.2, 7, 7
Point B was measured as the reference point.
I don't know how to obtain the forces with just this information.
You would use your rubber band calibration results to translate lengths into forces.
I checked to make sure you had done those calibrations. Having done so it's easy to send you a copy for convenient reference:
7.6, 8, 7.9, 7.6, 8, 6.8 ( 1 domino / 0.19 N )
7.6, 7.4, 7.2, 7.5, 7.6, 7 ( 2 dominoes / .38N )
7.9, 7.5, 7.4, 7.5, 7.8, 7.4 ( 4 dominoes / 0.76N )
8, 7.7, 7.7, 7.7, 8, 7.8 ( 6 dominoes / 1.14 N )
8.3, 8.2, 7.9, 8, 8.6, 8 ( 8 dominoes / 1.52 N )
9, 8.3, 8.1, 8.1, 8.8, 8.2 ( 10 dominoes / 1.9N )
** Net force and net force as a percent of the sum of the magnitudes of all forces: **
The forces were not found.
** Moment arms for rubber band systems B and C **
11cm, 12cm
The moment arc is the distance from the fulcrum to the end of the rubber band at each point.
** Lengths in cm of force vectors in 4 cm to 1 N scale drawing, distances from the fulcrum to points B and C. **
7, 7
11, 12
The first line is the length of the rubber bands represented by vectors in the drawing.
The second line is the distance from the fulcrum to the rubber bands.
** Torque produced by B, torque produced by C: **
I didn't notice the rubber bands to be forcing the rod one way or the other. It seemed to be pretty balanced. I'm not sure how I would calculate the torque.
** Net torque, net torque as percent of the sum of the magnitudes of the torques: **
Torque was not found.
** 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: **
You need to use your rubber band calibrations to find the forces. See my note. Then fill in the rest and simply resubmit.