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7. Evaluation of Experiment Results
Some useful Matlab functions and ideas will be provided here. If you find yourself new to Matlab, We After conducting the pendulum experiment 6C, you should have received a mail with your measurement results in the form of a *.mat file. The handling and explanation about elements in said *.mat file can be found above. Now it is time to analyze and interpret the acquired data. For this, you should be using Matlab to plot the data, perform calculations and transform your results to answer VIPS questions. If you find yourself new to Matlab, we recommend using the tutorial, as it provides a great starting point.
!!! ATTENTION !!!
Each VIPS exam is only for entering the results and therefore limited to 30min! You should prepare your answers beforehand, as the calculations may require more time than is available during the VIPS. Below you will find the collection of all VIPS questions regarding experiment 6:
7.1 Choosing a Suitable Sensor 1/3 - Single Choice
The environment of an application requires sensing of acceleration over one axis at 90 °C.
Which sensor should be used?
- ASC 4221 MF
- ADXL 377
- ADXL 335
7.2 Choosing a Suitable Sensor 2/3 - Single Choice
An application requires acceleration sensing in 3 axes with a range of ±2 g. (Hint: The non-linearity error of the sensors would be a decisive factor!)
Which sensor should be used?
- ASC 4221 MF
- ADXL 377
- ADXL 335
7.3 Choosing a Suitable Sensor 3/3 - Single Choice
An application requires 3-axes acceleration sensing with a range of ±16 g and a maximum resolution of 7 mV/g.
Which sensor should be used?
- ASC 4221 MF
- ADXL 377
- ADXL 335
7.4 Experiment 6B - Tilting the ADXL345 - Numerical Input
In part 6.2 you titled the sensor in different angles and read the values of the acceleration on the z-axis.
Find the acceleration values on the z-axis for six different angles and create a table.
Please enter your table values as follows:
| sensor angle in Degree ° | acceleration value on z-axis in m/(s^2) |
|---|---|
| 0° | 1 |
| 30° | 2 |
| 45° | 3 |
| 90° | 4 |
| 180° | 5 |
enter your table like this:
[0 1; 30 2; 45 3; 90 4; 180 5]
Please use the decimal point and give only numerical values in degree, respectively m/(s^2) as in this example: [0 1; 30 2; 45 3; 90 4; 180 5]
7.5 Experiment 6C 1/4 - Manual Displacement: Angle Correlation - Numerical Input
In experiment 6C, you've conducted the measurement A, where you manually displaced the pendulum. You have noticed that the measured angle does not match the pendulum displacement you have observed during the measurement. You now want to recover the angle over time from the acceleration over time by using the relationship between deflection and gravity. Use the acceleration in the x axis to derive the maximum angle you have manually deflected.
What is the maximum angle, that you have displaced the pendulum to in degree?
Please use the decimal point and give only numerical values
7.6 Experiment 6C 2/4 - Free Oscillation: Pendulum Frequency - Numerical Input
In experiment 6C, you've conducted the measurement B, where you initially displaced the pendulum and observed its free oscillation. From the acceleration in the x axis, you want to derive the pendulum frequency. The acceleration in the y axis and a sketch can help to understand the behavior tracked in the x axis.
What is the pendulum frequency in Hz?
Please use the decimal point and give only numerical values.
7.7 Experiment 6C 3/4 - Free Oscillation: Centri Petal / Centri Fugal Acceleration - Numerical Input
In experiment 6C, you've conducted the measurement B, where you initially displaced the pendulum and observed its free oscillation. During the circular movement on the circular track, the mass inside the acceleration sensor experiences the centri fugal/ centri petal force. The force causes an acceleration of the masses along the pendulum axis and points in a 90° angle to the tangential line at the circular track. You want to use the information about the pendulum angle to calculate the centri fugal/ centri petal acceleration in the point, where the acceleration in x equals 9.81 m/(s^2). Hint: Consider the direction of acting forces in this point.
What is the centri fugal / centri petal accelerationexperienced by the mass inside the accelerometer, where the acceleration in the x axis is equal to 9.81 m/(s^2)? Give the answer in m/(s^2)
Please use the decimal point and give only numerical values.
7.8 Experiment 6C 4/4 - Free Oscillation : Maximum Velocity - Numerical Input
In experiment 6C, you've conducted the measurement B, where you initially displaced the pendulum and observed its free oscillation. The acceleration in the y axis describes the acceleration that is tangential to the circle track of the pendulum. You are interested in the highest tangential velocity.
What is the highest tangential velocity along the circle track of the pendulum in m/s?
Please use the decimal point and give only numerical values.