Phy 121
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: **
i don't have the threaded rod in in my lab kit or the plywood, i found some items in my garage and will do the best i can
** 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: **
-7,0,6
8,8.4,8.3
.9,1.9,1.6
the origin which is where the center hook connected to the rod
the forces in Newtons were obtained by making the best fit straight line on the graphs and finding the force for the corresponding length
** Net force and net force as a percent of the sum of the magnitudes of all forces: **
-.6N
14%
the first number is the net force by adding -.9+-1.6+1.9 = -.6N
sum of the magnitudes .9+1.6+1.9 = 4.4N then .6 / 4.4 = 14%
** Moment arms for rubber band systems B and C **
7,6
these are the moment-arm for the distances from the fulcrum to point B and point C, they are measured from the center to each given point
** Lengths in cm of force vectors in 4 cm to 1 N scale drawing, distances from the fulcrum to points B and C. **
3.8,7.8,6.4
7,6
the top numbers are the length of the vectors represented by the forces in the given direction, the second line numbers are the lengths from the fulcrum to the points of application of the two downward forces
** Torque produced by B, torque produced by C: **
+6.3,-9.6
the torgues were the product of the moment arm and the force of the given vector, vector B is positive because its direction is in the counterclockwise direction, vector C will be negative because its direction is in the clockwise direction
** Net torque, net torque as percent of the sum of the magnitudes of the torques: **
-3.3
21%
-9.6+6.3=-3.3, 9.6+6.3=15.9, 3.3/15.9 *100 = 21%
the first line is the net torque of the system and the second number is the percentage of the net torque to the sum of the torque
** 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? **
1hr 10min
** Optional additional comments and/or questions: **
i only did the first part of the experiment
For your course only the first part is required.
Your work looks good.