After setting up the apparatus to give fair results I will carry out four sets of ticker timers for the force and then for the mass of the trolley. These will then give me a series of ticker tape charts which I will be able to transfer onto an acceleration against force graph and acceleration against mass graph.
Prediction
I predict that the force will be proportional to the acceleration and so will also the mass will be proportional to the acceleration. However not in the same way, as the force increases the acceleration will increase but as the mass increases the acceleration will decrease.
Planning
Safety: There are a few safety precautions that we need to take, such as making sure that the weights, when they came down, do not hit anyone who may be passing, or on our own feet. Another precaution is making sure that the weights on the trolley are securely placed, or fastened, to the trolley, so that they do not come off from the trolley and cause injury.
Equipment: I will need a special ramp with elastic at one end, books to put under the ramp to get elevation, but the elevation must be so that it is a friction/gravity compensated. A trolley, a ticker timer and tape. String to tie the falling weights to the trolley. Weights with 100g masses on, and also masses of 1kg for the trolley.
Fair test: Making sure that the tests are fair is quite a major factor in our experiment, because we have to keep all the experiments the same i.e the method in which we do it has to keep the same.
Predictions: I predict that the more kilograms that are put on the trolley, the slower the trolley will go down the ramp.
Procedure: When the equipment is set out as above then we will tread some ticker tape through the ticker timer and Cellotape the end to the trolley. I will put the trolley at its starting position (at the start of the ramp) and then when I am ready I will start the ticker timer and start the trolley down the ramp, and when it reaches the end I will stop the ticker timer.
I have decided to take measurements of 2 newtons pulling the trolley down (which will always stay the same) and then change the different weights on the trolley itself, from nothing up to 4 kilograms, which include 1kg, 2kg, 3kg and 4kg. So in all I will do 5 experiments and therefore have 5 different graphs.
We have not really done any previous experiments like this one apart from in the FY we did some experiments like these using the ticker timers and tape, and so before I started I knew roughly what was to be expected.
Evaluating Evidence
I think that the procedure which I used was the best that I could have done, partly because the results I got were very good. On looking at my results I can tell that they are quite good because the line of best fit goes roughly through the top of all the results. Also the acceleration of the trolley became less the more weight was put on.
The method that I used was quite a reliable one and there were not very many problems that occurred from carrying out the experiment, the only slight improvement that I would do, which may not actually affect my results very much would be if, as I did, you took the readings in two different lessons and then used two different trolleys, the trolleys may run differently and so the readings will be different, but as I said it may not affect the graphs too much.
But apart from that the method that I used was completely successful.
From looking at my results I can see that the graph where there is 1 kilo gram
on the trolley the last piece of ticker tape is out of place because the other pieces of tape match up roughly to the line of best fit whereas the last one is equal to the previous piece of tape before that. This could have been caused by a number of things such as something may have very slightly obstructed the trolley on its way down the ramp, or perhaps the trolley got up to a constant speed and so would go no faster. Or possibly it was just a freak reading. If I was allowed to repeat any experiments again then I would definitely repeat this experiment, to get a full set of correct results. When I was working out the acceleration, for that experiment I did not include this piece of tape and so I only divided the number I got by seven rather than eight. I think that this was a good idea because is meant that my results kept almost perfect and it did not affect the acceleration at all.
My prediction was completely correct because I said that the more weight that was put on the slower the trolley would go, and I have enough evidence to confirm that my prediction was correct.
Analysing evidence and conclusion
We can conclude that the more weights that are put on the slower the trolley goes down the ramp. The reason for this statement to be true is because the more weight that is put on the trolley the more downwards force is exerted on the trolley, and the force is greater than gravity and so it goes slower down the ramp than it would do if I had no weights on it. It also causes more friction between the ramp and the wheels of the trolley and so therefore goes even slower down the ramp. My results compare very well with my predictions because I said that the more weights that were put on the trolley the slower it would go and as my results showed I was correct.
