- Level: International Baccalaureate
- Subject: Physics
- Word count: 1021
Motion due to a Steady Force - Lab
Extracts from this document...
Introduction
Timmy Bendiš – 10.11.2008 – 3mm
Motion due to a steady force
Aim
Verify Newton’s 2nd law of motion
Variables
Independent:
mw - Mass of the weight
mt - Mass of the trolley (controlled, kept constant)
s - Distance (controlled, kept constant)
Dependent:
Δt - Time (measured)
a - Acceleration (calculated from measured time and distance)
F - Pulling Force (calculated from mass mw)
Fair test:
We presume this test to be fair, because all variables of the system are kept constant, except mass of the weight that generates pulling force that we presume affects the acceleration of the trolley, which is what we want to measure.
Materials
- trolley
- 10 different weights (for 10 different trials)
- string (to make the trolley travel in a straight line and have the weights pull it down... the weights are tied to the string which is tied to the trolley.)
Middle
10
0,251
1,101
0,63
1,07
Table 1. Mass of the weights and trolley travelling times
Data Processing
In Table 2, we processed the collected data from Table 1, using the following formulas :
Applied pulling force = mwx g
Measured acceleration
Measured pulling force =
Uncertainty of measured acceleration (sample for trial #1):
Estimated reaction time is 0,2 seconds
Ideal acceleration (per Newton’s 2nd law)
Trial | Applied pulling force (N) | Measured acceleration (ms-2) |
Conclusion
Sources of error
- It was difficult to precisely measure time. Our reaction time was large compared to the travelling time of the trolley. This contributed the most to the acceleration uncertainty.
- We measured time only once for each trial.
- We ignored the friction, since we angled the table. But, we suspect that friction also contributed to the uncertainty of the results.
Improvements
- Lengthen the trolley travelling time to reduce the relative time measurement error. For example, we could raise table and lenghten the string.
- Measure the time in each trial multiple times (three at the minimum).
- Eliminate some of the smaller weights from the measurement, to minimize effect of the friction force at lower speeds.
- Use smoother surface.
- Keep total mass constant. This means that we start with maximum Weight and move the mass from the Weight to the trolley for each trial. Then the lines in both graphs would be more linear.
This student written piece of work is one of many that can be found in our International Baccalaureate Physics section.
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