Module F
Sciences with
TI-NspireTM Technology
Lesson 2: Free fall acceleration
TI-NspireTM Technology
In the previous lesson you learned…
 What is meant by the scientific method;
 That students are stimulated to do inquiry based science;
 That TI-NspireTM Technology can be a great help in inquiry based
learning;
 How the Vernier DataQuest application can be used to do an
experiment in an easy way;
 How you can analyze data by using the Vernier DataQuest
application;
 That TI-NspireTM Technology offers different ways of making a report
of a science experiment.
2 | Lesson F.2
TI-NspireTM Technology
In this lesson you will:
•
•
•
Measure the free fall
acceleration;
Investigate the influence of the
air during a free fall;
Use the Vernier DataQuest
application and the CBR2
motion sensor.
3 | Lesson F.2
Free fall acceleration
•
•
•
Near the surface of the Earth, an
object in free fall in a vacuum will
accelerate at approximately 9.8 m/s2,
independent of its mass.
This is what Newton taught us.
Isn’t it possible to measure this free
fall acceleration?
4 | Lesson F.2
Experiment 1
•
•
•
One of the benefits of having sensors in
your school lab is that you can measure
this in an easy way.
All you need is a basketball, a motion
sensor and the Vernier DataQuest
application.
This is how it works:
1. Hold the sensor about 1.5 meters
above the ground;
2. Let the basketball fall;
3. Measure the motion of the bouncing
ball;
4. Analyze the data.
5 | Lesson F.2
Conclusion
•
The curve fit showed us that the position function of one bounce
can be written as
x(t )  4.860t 2  12.336t  8.806
•
The derivative of this functions is the velocity:
v x (t )  9.72t  12.336
•
The derivative of the velocity is the acceleration:
ax (t )  9.72
6 | Lesson F.2
Experiment 2
•
•
•
In the first experiment we have
seen that the influence of air
resistance on the movement of the
ball was negligible.
What would happen if we
investigate the free fall of a coffee
filter?
Will the acceleration still be close
to 9.8 m/s2?
7 | Lesson F.2
Conclusion
•
The curve fit showed us that the position function of the filter can be
written as
x(t )  1.021t  0.266
•
The derivative of this functions is the terminal velocity:
v x (t )  1.021
•
•
The terminal velocity depends on many factors including mass,
drag coefficient, and relative surface area, and will only be
achieved if the fall is from sufficient altitude.
The derivative of the velocity is the acceleration:
ax (t )  0
8 | Lesson F.2
Conclusion
•
We can conclude that the value of 9.8 m/s2 is only valid, when air
resistance can be neglected.
9 | Lesson F.2
In this lesson you learned:
 That the Vernier DataQuest application automatically chooses the
standard setting at the start of the application, depending on the
connected sensor;
 To change the collection setup of an experiment with a motion
sensor;
 That you can select a region of the collected data, before you do a
curve fit;
 That the derivative of the position function gives the velocity function
and that de derivative of the velocity function gives the acceleration
function;
 That air resistance has an important impact on the free fall
acceleration.
10 | Lesson F.2
Congratulations!
You have just finished lesson F.2!
11 | Lesson F.2