course PHY 231
I responded to my last revision with *******. I apologize for not using the symbols you wanted me to originally use. From now on I will use &&&&&&##.
&&&&&&##My error with the rubber bands were they were more than 8 cm and I recorded lengths of 3+cm. I recorded how much they were stretched, and I wanted to stay consistent so I carried it this way throughout the experiment. Using the numbers that way does throw off future calculations but everything stayed proportional. The left side was my
Please let me know what else I need to do so this will be considered acceptable&&&&&&&&$##
torques
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: **
** 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: **
0cm, 5.5cm, 13.0cm The very left point is the initial point 0.
3.50cm, 4.50cm, 5.55cm
The rubber bands are more than 8 cm long; these cannot be the correct lengths.
0.19N, 0.95N, 0.88N
I wanted to use the very left as a reference point to avoid negative positions
I used information from an earlier experiment(force calibrations) that showed how much a rubber band stretched was equal to a certain force. I applied that to this experiment accordingly.
That is the right thing to do, but the lengths you give here do not correspond to valid rubber band lengths and it is difficult to see how these forces were obtained from the information you have reported.
All of the centimeter positions were obtained by using the ruler, measuring distances of the rubber band length. I also chose what I wanted to use for my reference points. The first intersection the left was point zero.
** Net force and net force as a percent of the sum of the magnitudes of all forces: **
2.02N
Some of the rubber bands and upward and some act downward. The sum of the forces must include positive and negative values of the force. The sum of the magnitudes of the forces you give above is 2.02 N, but the sum of the forces is not 2.02 N.
If I want a percent of each individual to the whole(I'm assuming that is what you want), then from B to C like this has always been is:
9%, 47&, 44%
These are the forces I am asked to be solved for. The net force, the percent sum, and now I am explaining it.All of the forces were downward moving in the same direction. This means that the net force was the sum of all forces in this particular experiment.
** Moment arms for rubber band systems B and C **
.54N, 1.2N
The rubber band C still has the dominoes against it, which puts a much stronger force in it than Rubber Band system B
** Lengths in cm of force vectors in 4 cm to 1 N scale drawing, distances from the fulcrum to points B and C. **
3.5cm, 5.0cm, 5.5cm
2.5cm, 3.2cm
These are all the distances from the fulcrum to the points of application. With the stress of the dominoes on Rubber band system C, the force and torque and distance is extended.
** Torque produced by B, torque produced by C: **
3.84Ncm negative
3.5Ncm positive
** Net torque, net torque as percent of the sum of the magnitudes of the torques: **
47%
52%
Due to significant figures and uncertainties of estimation the percent sum will rarely go directly to 100%. This is the ratio of one torque solution to the sum of the torques.
** Forces, distances from equilibrium and torques exerted by A, B, C, D: **
2.7N +, 2.9N -, 1.9N -, 2.3N +
This is the forces measured and calculated from the experiment.
** 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: **
0.2N
My picture(followed step by step from the instructions) was very similar in the diagram structure. This is just a vertical motion. There are more forces acting on the rod such as the tension in the rubber band that we do not put into account.
** Net torque for given picture; your discussion of whether this figure could be accurate for a stationary rod: **
23.4Ncm
This is not entirely close to a realistic torque. We cannot have simply one vertical direction and assume that is the net torque. For a bridge many more factors are necessary, and more direction.
** 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: **
13.5Ncm
0.2N, 9.8N
2%
470.4Ncm, 23.4Ncm
This is the torques about a certain point, resultant forces and magnitudes of forces, percent sums, magnitudes and resultants of torque.
** 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: **
17.5Ncm
0.5N, 9.8N
2%
470.4Ncm, 23.4Ncm
This is the torques about a certain point, resultant forces and magnitudes of forces, percent sums, magnitudes and resultants of torque.
** In the second setup, were the forces all parallel to one another? **
They were not exactly parallel but they did not differ by more than 5 degrees
** Estimated angles of the four forces; short discussion of accuracy of estimates. **
5degrees
They were almost parallel and differed very little. It was almost negligible.
** x and y coordinates of both ends of each rubber band, in cm **
(0,0), (0,-5), (2,3), (2,3)
(3, 5), (3,9), (2,3), (3, 9)
(5,0), (7, -5), (5, -9), (2,3)
These are all confusing coordinates I am asked to plot. I can easily calculate how long each point is either with a ruler or the pythagorean theorem.
** Lengths and forces exerted systems B, A and C:. **
3cm, 4N
4.7cm, 4.5N
2.7cm, 2N
These are all simply the lengths of each rubber band and the forces that I calculated.
** Sines and cosines of systems B, A and C: **
30degress,
40degrees
** Magnitude, angle with horizontal and angle in the plane for each force: **
4N
4.5N
2.7N
** 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): **
3N, 2N
2N, 3N
1N, 1.3N
These are the x and y component forces
** Sum of x components, ideal sum, how close are you to the ideal; then the same for y components. **
6N, 6N, they are close
6.3N, 6.3N, they are close
These are the x and y components I am still asked to find
** Distance of the point of action from that of the leftmost force, component perpendicular to the rod, and torque for each force: **
18.3Ncm
22.5Ncm
28Ncm
This is torque, again what I am being asked to solve by multiplying the force found earlier by the distance again found earlier.
** Sum of torques, ideal sum, how close are you to the ideal. **
68.6Ncm
This is the sum of the torque from aboe
** How long did it take you to complete this experiment? **
180 minutes
** Optional additional comments and/or questions: **
I haven't commented on the entire report at this point, because I'm not sure of the information you give near the beginning. Can you insert some clarification into a copy of this document and Mark your assertions with ####?
The clarification on your measurements makes sense of everything else. This one is OK.