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CourseworkHelp
:Trolley Investigation
Factors
û Gradient/Angle/Height
û Surface type of ramp
û Weight/mass of trolley
û Surface of wheels
û Force applied
û Amount of wind resistance
û Aerodynamics of trolley
Aim:
To see how the angle of a ramp affects the speed of a trolley down the ramp.
Hypothesis:
I believe that as the height of the ramp is increased the speed of the trolley will also increase. This is because of the potential energy given to the trolley when it is pushed up the ramp. We can work this out by using this formula:
E = m x g x h
We know two of the factors that are in this experiment:
M = 0.8
G = 10
To work out ‘h’ we can use trigonometry
1m
h
‘h’ is worked out by using sine the formula being:
Opp
Sin θ Hyp
This formula can be changed to the following:
Sin θ x 1m = h
Using this formula you can get the following heights:
|
Angle (°) |
Height (m) |
|
3 |
0.052 |
|
6 |
0.10 |
|
9 |
0.16 |
|
12 |
0.21 |
|
15 |
0.26 |
|
18 |
0.31 |
|
21 |
0.36 |
|
24 |
0.41 |
|
27 |
0.45 |
|
30 |
0.5 |
Then the potential energy can be worked out by using the above formula (P = m x g x h) it is shown in the table below
|
Height (m) |
Calculation |
Potential energy (J) |
|
0.052 |
0.8 x 10 x 0.052 |
0.416 |
|
0.10 |
0.8 x 10 x 0.10 |
0.8 |
|
0.16 |
0.8 x 10 x 0.16 |
1.28 |
|
0.21 |
0.8 x 10 x 0.21 |
1.68 |
|
0.26 |
0.8 x 10 x 0.26 |
2.08 |
|
0.31 |
0.8 x 10 x 0.31 |
2.48 |
|
0.36 |
0.8 x 10 x 0.36 |
2.88 |
|
0.41 |
0.8 x 10 x 0.41 |
3.28 |
|
0.45 |
0.8 x 10 x 0.45 |
3.6 |
|
0.5 |
0.8 x 10 x 0.5 |
4 |
From the above calculations we can see that the largest height has the most amount of potential energy. This amount of potential energy would only be achieved in a vacuum, but we do not have a vacuum this could only be carried out with specialist equipment, which we do not have. If this were possible we would see higher speeds, as there is no loss of speed due to the absence of friction.
Factors that could affect this experiment are the following:
û Angle of the Ramp
The experiment could be affected by the angle of the ramp for example a 10° angle could have a higher amount of potential energy than a 3° angle.
û Surface type of ramp
The surface of the ramp may affect the outcome of the results because any type of grip on the surface could slow it down and also such things as lubricants on the ramp could make the ramp slippery in effect speeding up the ramp.
û Mass of the trolley
The mass of the trolley affects the results because the weight could either slow it down or even speed the trolley up, as there will be a greater amount of potential energy pulling on the trolley.
û Surface of wheels
The surface of the wheels could affect the trolley because just like the ‘surface type of the ramp’ the wheels could slow it down, as this is the effect of any type of traction provided by the wheels.
û The aerodynamics of the trolley in relation to wind resistance
The diagram shows how the air reacts in relation to the object to which it is to pass. It shows that an object such as the aerofoil is the most aerodynamic. This means that the results will be affected by how aerodynamic the trolley is.
 |
Preliminary Work
I carried out some preliminary tests to see any problems, which could occur and anything, which could be improved. I first tried timing the trolley with a ticker timer. I place the ramp at an angle of 5° to test the ticker timer. I attached the tape to the back of the trolley and turned on the ticker timer whilst letting go of the trolley the result was 96 dots. Which meant in seconds is 96/50 = 1.92 seconds. Although we felt this was accurate we felt it would be very time consuming to count 40-50 lengths of tape. So we decided to use a stop-watch although this may be slightly inaccurate because of the result being reliant on the timers reactions, we felt this to be most efficient. By setting at 5° we got a result of 1.39s. The results of the experiment with the stopwatch are shown below
Preliminary Experiment
|
Angle (°) |
Time 1 (s) |
Time 2 (s) |
Time 3 (s) |
Average (s) |
|
5 |
1.59 |
1.42 |
1.69 |
1.50 |
|
10 |
0.98 |
0.91 |
1.02 |
0.97 |
|
15 |
0.77 |
0.78 |
0.73 |
0.76 |
|
20 |
0.53 |
0.61 |
0.64 |
0.59 |
After the 20° angle we found it was becoming difficult to time the trolley and also to support the ramp. So we decided to change the range from 5°- 45° to a more suitable range of 3° - 30° and also to carry out the experiment 5 times instead of the 3 allowing us to get a better average.
Apparatus:
ü Trolley
ü Ramp
ü Metre stick
ü Angle measurer
ü Stopwatch
ü A materials to hold up the ramp e.g. books
Diagram:
Method:
û Collect the apparatus
û Set-up as shown in the diagram
û Set the angle of the ramp at 3°
û Mark in a start line
û Mark 1 meter from the starting line
û Place he trolley at the top of the ramp and let go
û Start the timer when the trolley passes the start line
û Stop the timer when the trolley passes the finish line.
û Put the result into the result table and repeat experiment 5 times
û Add 3° to the angle and repeat the experiment
Fair test
The experiment will be a fair test as there will only be one variable factor: the angle. All the other factors will stay the same such as the material used and the trolley used this means that there will not be any bias issues in this experiment. Other factors that might affect the experiment may be that of the angle being ±0.1°
Results
Final tests
|
Angle (°) |
Time 1 (s) |
Time 2 (s) |
Time 3 (s) |
Time 4 (s) |
Time 5 (s) |
Average (s) |
|
3 |
1.95 |
2.10 |
2.18 |
2.32 |
1.96 |
2.10 |
|
6 |
1.40 |
1.51 |
1.48 |
1.35 |
1.30 |
1.41 |
|
9 |
1.02 |
1.01 |
0.94 |
0.98 |
1.01 |
0.99 |
|
12 |
0.98 |
0.99 |
0.89 |
0.94 |
0.98 |
0.96 |
|
15 |
0.80 |
0.77 |
0.76 |
0.79 |
0.82 |
0.78 |
|
18 |
0.65 |
0.67 |
0.63 |
0.64 |
0.59 |
0.64 |
|
21 |
0.62 |
0.54 |
0.61 |
0.60 |
0.50 |
0.57 |
|
24 |
0.44 |
0.48 |
0.46 |
0.46 |
0.51 |
0.47 |
|
27 |
0.42 |
0.38 |
0.41 |
0.37 |
0.45 |
0.41 |
|
30 |
0.34 |
0.41 |
0.38 |
0.33 |
0.35 |
0.36 |
From the results I could then find the speed at which the trolley travelled down the ramp this is worked out by the formula
Speed = Distance
Time
The speeds are then shown in the table:
|
Angle (°) |
Time (s) |
Speed (m/s) |
|
3 |
2.10 |
0.48 |
|
6 |
1.41 |
0.71 |
|
9 |
0.99 |
1.01 |
|
12 |
0.96 |
1.05 |
|
15 |
0.78 |
1.30 |
|
18 |
0.64 |
1.57 |
|
21 |
0.57 |
1.74 |
|
24 |
0.47 |
2.13 |
|
27 |
0.41 |
2.46 |
|
30 |
0.36 |
2.76 |
Conclusion
From looking at the results it is clear that both my aim and predictions were achieved and that the prediction was correct. I also found that the speed was increased and that the potential energy increased with the angle. Looking at the graphs shows that the results were mainly affected by the angles between 3° - 15°. The second graph shows a positive correlation between the angle and the speed.
Evaluation
I felt that the experiment was done to the best of my ability and went well overall. I did all that I could to ensure that the investigation was fair except for the fact that we used a stopwatch instead of a ticker timer. Although another negative side being that the books that we used to hold up the ramp could have one of two effects. One that they could alter the angle slightly which affects the results. Two it may allow the wood to slip or even tilt to one side which may effect the results too. Using the books and the stopwatch were both not scientific which meant that the results could be possibly bias. To improve the investigation I would redo the experiment in the same fashion but use the ticker timer and a better material to hold the ramp in place. Although I still feel that my results were accurate enough to draw a firm conclusion as I had repeated the experiment 5 times and found an average which gave the desired result.
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