# Science Course Work : Free Fall

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Introduction

Science Course Work : Free Fall Planning I am going to investigate the effects of changing the spinners speed on the drag. There are several variables that I could investigate to see their effects on the spinners drag. 1. Shape- I could alter the shape of the spinner 2. Size- I could investigate the effects on drag with different sizes of blade 3. Speed- I could change the weight to increase or decrease the speed. Shape- if I changed the shape of the spinner the air resistance would change. For a ball of paper to accelerate at the same speed as a smaller spinner would require more force (gravity) and hence would need more weight to fall at the same speed. This is because more air is having to be displaced to fall the same distance as on object of similar mass which has a more stream line shape. Size- Larger blades on the spinner would mean more potential energy would be dissipated acting like a parachute and making it fall slower. The opposite happens with smaller blades. Speed- By using the fact that at terminal velocity Drag is equal to weight. I can calculate the speed by weighing the spinner with different masses. Doing this I can investigate how terminal velocity is effected by weight. Another factor that could be considered is air conditions. Aeroplanes/gliders perform differently when it is raining than when it I sunny. Is this also try for spinners? One of the problems when investigating this is that it would be difficult to keep the other variables constant. ...read more.

Middle

I intend to try and prove this theory or to find out what is actually happening to a spinner's drag. Results The know formulae I have used to calculate a formula for terminal velocity relies on the fact that A (acceleration) is constant, meaning that the spinner accelerates at the same rate until it reaches terminal velocity. Constant acceleration requires a constant resultant force, resultant force can be calculated by subtracting the drag of an object when falling from its weight. During acceleration the weight remains constant, however the drag increase until terminal velocity is reached; this means that the resultant force decreases as the spinner gets nearer to terminal velocity. As the resultant force is not constant, I can not presume that acceleration is also constant. The formula I used all assume A as a constant, this means that my equation for Vt and the results I have based my conclusions on are likely to be slightly incorrect. If I had taken into consideration the effect of resultant force on drag in my equations the results would be more reliable. Weights: 1 paper clip = 0.41g 1 paper clip with spinner =1.09g 2 paper clips = 0.81g 2 paper clips with spinner = 1.48g 3 paper clips = 1.19g 3 paper clips with spinner = 1.86g 4 paper clips = 1.58g 4 paper clips with spinner = 2.25g 5 paper clips = 1.96g 5 paper clips with spinner = 2.63g 6 paper clips = 2.35g 6 paper clips with spinner = 3.02g Spinner = 0.67g Height of ceiling = 2.75 cm Mass of spinner No. ...read more.

Conclusion

Evaluation I am fairly confident that my results are accurate as I did them several times and used a balance that calculates mass to one hundredth of a gram. I also made sure we used the same make of stopwatch each time. A factor, which could have effected the accuracy of my results, is human reaction times and human error. This will mean that the results are slightly out however as this was the same for each of the different masses of the spinner I feel I can still draw some accurate conclusions. We identified anomalous results as we went along, repeating the drop and using these new results to work out the averages not the anomalous readings. I would think these anomalous readings were due to human error. As a result of identifying anomalous readings as I went along my final graphs have no points which are not on or very close to the line of best fit. My results are fairly consistent, there is not a lot of variation. I feel that with more evidence to support my prediction I could be 100 % sure that my conclusions are accurate, however we only used six different masses of spinner so I can not be altogether certain that the conclusions I have drawn are correct. I believe my results back up the predictions I made adding evidence to my theories. I think that to improve the validity of my conclusion I should have found a way of tacking more times and points to plot on my graph. This would make me more confident that my conclusion is as accurate as possible. ?? ?? ?? ?? 4 1 ...read more.

This student written piece of work is one of many that can be found in our GCSE Forces and Motion section.

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