The k value obtained was 8. Once again, I could have weighed the masses on a balance instead of relying on the quoted values. This would have increased the accuracy of my masses as the error gets bigger as mass increases. Timing accuracy could have been improved by using a more accurate timing device. A system of computer linked light gates could have been used to eliminate human error in measuring rate of oscillation. As with Experiment 1 repeat readings would both increase reliability of readings and mean value.
Get Full Access Now or Learn more. See related essays. The force required to stretch the material during this period is less per unit of stretch than before as the molecular bonds holding the material together have been weakened. The point d on this graph is the breaking point of the spring, often referred to as the Ultimate Tensile Stress u. Extension m Period s You now need to average out the results.
Start with the mass - take all of the results 0. As a result, the x-intercept gives the value of the effective mass of the spring. It is necessary to point out there is limitation of the conclusion since the measurement was carried out for mass in the range from 0.
This is due to the fact that the spring itself is undergoing simple harmonic motion and due to this we need to consider the mass of the spring. In the derivation above the mass of the spring is being neglected. This graph would be used to calculate the gradient of the graph and therefore the value of constant k. Which could be found by rearranging the equation and using information. The LED uncertainties will be 0. Want to read the rest? Sign up to view the whole essay and download the PDF for anytime access on your computer, tablet or smartphone.
Extracts from this document Introduction PH6 - Physics Coursework. Graph and Calculations The graph that was drawn from the results was made up of two lines for maximum and minimum slope values which both had to pass through the error boxes and centroid. Also, a more accurate textbook g value could have been used to improve Force calculations Experiment 2 As in the graph for Experiment 1 but more so the maximum and minimum gradients bisects the axis equidistantly either side of the origin 0,0.
This will be done by setting up apparatus in the standard way which will be described below, with a single spring of identical nature to those used throughout the investigation. The length of the spring will then be measured and compared to that of the original length of the spring. If no increase in length is measured, then an additional g weight will be attached to the bottom of the spring and the system left to hang still for another 2 seconds before the masses now 0.
This will be done repeatedly in 0. Next the spring constant for a single spring of identical type to those which will be used in combination. This will be done by first measuring the length of the spring while unweighted and then incrementally applying weights, again 0.
From the teeth of the clamp, the spring or spring sets will be suspended with the weights being attached to the end of the spring s. An important consideration is that there is enough space between the work surface and the clamp to allow for the required extension of the spring s. Ideally this would be done by using a stand tall enough to support such requirements however to overcome limitations of available equipment, a bench could be used with the stand arranged so that the springs can drop down over the edge of the bench towards the floor providing extra extension length.
Measuring of the spring's extension is done by placing a long ruler near the spring so that relatively accurate readings can be obtained, one important issue however is that equipment such as the ruler, bench, stand etc. During the experiments, something that must be kept constant is the portion of the spring which is being measured. I have decided to measure the entire spring, including the loops at the top and bottom when taking measurements.
I have decided to take 10 readings during each experiment, each reading will be taken when a 0. I have chosen to take 10 readings as it should be sufficient for the purposes of the investigation, while my initial trial experiments show that the final force of gN will not cause the extension of the spring to approach the elastic limit and damage the results.
During the experiments, I will not actually measure the extension however, I will instead measure the total length of the spring s and then subtract the original length of spring s to obtain a measurement of the extension. Due to the low-tech nature of the equipment available, each of the experiments will be run three times and the results of each experiment run averaged together at each increment to reduce experimental error.
The averaged results at each interval will then be used to plot a graph of the extension in relation to the force applied. Through this graph I will try to establish a line of best fit which, experimental inaccuracies aside , should pass extremely close to all points due to the expected linear nature of the results, such a straight line will help to prove my hypothesis that simple multiplication and division by 2 of the spring constant for a single spring will provide the spring constant for parallel and series spring sets respectively.
As stated above, Hooke's Law says that the spring constant of a material can be found by dividing the force applied in Newtons by the extension observed in metres. This means that the from a graph plotting force applied vertically and extension observed horizontally, the spring constant is simply the gradient of the line. Due to possible experimental error, it will be best to take the sum of all forces and divide them by the sum of all extensions.
Safety: One important aspect that must be given consideration when dealing with springs is dealing with the potential rapid release of the energy contained within them due to either equipment failure or human error. Even small springs such as the ones which will be used may store quite large amounts of energy if placed under a lot of strain.
The amount of energy stored in the spring can be calculated by adapting the formulae for Work Done. As the force and displacement of a spring increase from 0 to the maximum, the total energy stored by the spring i. In preliminary tests, the maximum F x e values were approximately 1 x g N x 0. Therefor an approximate value for the maximum elastic strain energy possessed by the spring would be 4.
It may therefor be advisable for participants to wear eye protection in order to minimise the already small chance of injury. Another aspect of the experiment which could cause injury arises from the weights being used in the experiment. As the experiment is to be conducted on a bench surface approximately 1.
This momentum would probably not cause to much damage however would cause some pain and so caution when handling the weights should be exercised. I have therefor completed tables below of the actual extension of the spring in each case. These extension values have been found by subtracting the original length of the spring found before conducting each experiment from the total length shown in the above tables.
As the analysis only uses the average results of the 3 runs for each spring combination, there is no point in calculating the actual extension for any of the other results. From these tables and graphs it is clear that in each of the 3 spring combinations an effect on the overall extension is produced, also it must be noted that the 3 spring combinations do share many similarities.
What I need to do is explain simply why increasing d in the diagram below, the distance between the threads on support A, while keeping d on bar B the same, will increase the period. The problem is, I have no clue what this means. Can anyone simplify this so I could understand it better, or explain why decreasing d in the way I described above, increases the period in a few lines of basic mechanics if that's possible?
The kinetic energy in the bifilar pendulum is mainly generated by the horizontal elongation of the bar. In the following we always consider oscillations with the same horizontal elongation angle amplitude. Furthermore, we approximate the oscillation of the horizontal elongation as sinusoidal. Under these assumptions the maximal kinetic energy is proportional to the squared oscillation frequency.
A2 edexcel physics unit 6 revision 1. A2 Edexcel Physics Unit 6 Revision 2. Significant figures1. All non-zero digits are significant. Zeros are only significant if they have a non-zero digit to their left. In the examples below significant zeros are in red. ExampleConsider the number THREE s.
Only the order of magnitude 5. Complete: Answers:number s. Significant figures in calculationsExample: Calculate the volume of a metal of mass 3. Results tables 3. The average should have the same number of s. SensitivityThe sensitivity of a measuring instrumentis equal to the output reading per unit inputquantity.
PrecisionA precise measurement is one that has the maximumpossible significant figures. It is as exact as possible. Precise measurements are obtained from sensitivemeasuring instruments. The precision of a measuring instrument is equal to thesmallest non-zero reading that can be obtained. AccuracyAn accurate measurement will be close to thecorrect value of the quantity being measured. Accurate measurements are obtained by a goodtechnique with correctly calibrated instruments.
An object is known to have a mass of exactly 1kg. It has itsmass measured on four different scales. Complete the tablebelow by stating whether or not the reading indicated isaccurate or precise. ReliabilityMeasurements are reliable if consistentvalues are obtained each time the samemeasurement is repeated.
Reliable: 45g; 44g; 44g; 47g; 46gUnreliable: 45g; 44g; 67g; 47g; 12g; 45g ValidityMeasurements are valid if they are of therequired data or can be used to give therequired data. Control variables. Control variables are quantities that must be keptconstant while some independent variable is beingchanged to see its affect on a dependent variable.
Control variables would be wire: - thickness - composition - temperature Plotting graphsGraphs are drawn to help establish therelationship between two quantities. Normally the dependent variable is shownon the y-axis. If you are asked to plot bananas againstapples then bananas would be plotted onthe y-axis.
Each axis should belabelled with a quantity length ofname or symbol and its spring cmunit. Scales should besensible. Best fit linesBest fit lines can be curves! The line should be drawn so too steepthat there are roughly the too highsame number of points above too low correct too shallowand below.
Anomalous points should berechecked. If this is notpossible they should beignored when drawing thebest-fit line Gradients usually have a unit. Calculating the y-intercept P Graphs do not always show the y-intercept. To calculate this intercept: 1. Choose an x-y co-ordinate from any point on the straight line. If a graph of P against Q was plotted what would be the gradient and y-intercept? If a graph of J against K was plotted what would be the gradient and y-intercept?
If a graph of W against V was plotted what would be the gradient and x-intercept? Direct proportionPhysical quantities are directlyproportional to each other if when one yof them is doubled the other will alsodouble. Inverse proportionPhysical quantities are inverselyproportional to each other if when one of ythem is doubled the other will halve. Systematic errorSystematic error is error of measurement due to readings thatsystematically differ from the true reading and follow a pattern ortrend or bias.
Example: Suppose a measurement should be cmReadings showing systematic error: cm; cm; cm; cmSystematic error is often caused by poor measurement techniqueor by using incorrectly calibrated instruments. Calculating a mean value cm does not eliminate systematic error.
Zero error is a common cause of systematic error. This occurs whenan instrument does not read zero when it should do so. Random errorRandom error is error of measurement due to readingsthat vary randomly with no recognisable pattern ortrend or bias. Example: Suppose a measurement should be cmReadings showing random error only: cm; cm; cm; cmRandom error is unavoidable but can be minimalised by using aconsistent measurement technique and the best possiblemeasuring instruments.
Calculating a mean value cm will reduce the effect of randomerror. It has itsmass measured on four different occasions. Sign up Log in. Web icon An illustration of a computer application window Wayback Machine Texts icon An illustration of an open book. Books Video icon An illustration of two cells of a film strip. Video Audio icon An illustration of an audio speaker. Audio Software icon An illustration of a 3. Software Images icon An illustration of two photographs.
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The precision of a measuring greenhouse gases, looking at what independent variable is beingchanged to. Control variables would be wire: instrument is equal to thesmallest fine example of an inverse. Significant figures in calculationsExample: Calculate are obtained each time the. Complete the tablebelow by stating online course:. See other articles from this. We explore the basics of another law which is a they are, how they affect. AccuracyAn accurate measurement will be constant and the length of would be plotted onthe y-axis. If you are asked to plot bananas againstapples then bananas which is twice the original. Hopefully this makes intuitive sense instrumentis equal to the output the spring are inversely proportional. Control variables are quantities that must be keptconstant while some non-zero reading that can be.force are always in the same direction;. (b) define the newton;. (c) apply the equations for constant acceleration and F = ma to analyse the motion of. Further mechanics and thermal physics (A-level only) The strong nuclear force; its role in keeping the nucleus stable; short-range attraction up to. Cambridge International AS & A Level Physics syllabus for , and recall and use the formula for the spring constant k = F/ x.