IB Physics Internal Assessment
Andy Tang
Research Question
In this internal assessment, I am given a cantilever to find the physical properties of it. I decide to investigate the relationship between the force I act on one side of the cantilever and the maximum acceleration the tail can reach. This experiment will be also showing the elasticity of the cantilever. Since I pull down one side of it and fixed the other side, when I cut the string, it will bounce up and down until all the internal energy is depleted. Text books

Newton meter
Accelerometer

Equilibrium line

Materials
1) A piece of cantilever that is made by acrylic plastic (length:35.2cm±0.1; Width:4.0cm±0.1; thickness:0.2cm±0.1) 2) An accelerometer (sensor; least count: 0.01ms^-2)
3) An Newton meter (the indicator points to 0 when it is hanging upside down; the least count is 0.25N; Measurement Range: 0N~5N) 4) String (length: 2cm *30)
5) 3 heavy texts book
6) A computer that has Logger Pro

Procedure
1) Set up the experiment as the graph shows
2) Connect the accelerometer with the computer
3) Adjust the sensor to zero when the cantilever is at the equilibrium 4) Adjust the indicator of Newton meter to zero when it is hanging upside down 5) Tie the string at the tail of the cantilever, hang the Newton meter to the other side of the string 6) Pull down the Newton meter, try to keep in the same position before cut the string 7) Cut the string

8) Collect the data that are created by computer
9) Redo (3)~(8) 2 more times for each test point

Dependent Variable
The dependent variable of my experiment is the maximum acceleration that the tail of the cantilever can reach. In the data process, I set this variable as the Y value. This variable is measured in meters per second square (m/s^2). Because the tail will bounce up and down, I will have both positive and negative values for acceleration. Having only one maximum acceleration value, I will probably not obtain the accurate information from the final result, because if the tension force is too big, the bounced back force might upspring the text books, then the data would not be precise. Hence I am going to collect not only the positive maximum values, but also the minimum values (I will written as “negative maximum value” in the rest of this IA) of the acceleration. Independent Variable

The independent variable of my experiment is the force I act on the tail of the cantilever. I pick ten different values (from 0.75 to 3.0, where increases by 0.25 for each test point) for it and it is measured in Newton (N). In the graph, this will be shown as the Y value. The capacity of the force will affect the maximum acceleration. Controlled Variable

There are several variables that need to be controlled in this experiment. First of all, t...

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