Kinematics- Lab Report
Investigating the changes in the acceleration and
deceleration of an object
10/12/2014
Mr Balajee
Kalina Fadel
Table of Contents
Aim: ............................................................................................ 3
Hypothesis: ................................................................................. 3
Variables: .................................................................................... 3
Method: ...................................................................................... 3
Safety precautions: ..................................................................... 4
Results: ....................................................................................... 4
Evaluation: .................................................................................. 5
Conclusion: ................................................................................. 5
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Aim:
The aim of this experiment is to observe the different speed at which a ball
will travel on flat ground at different intervals.
Hypothesis:
If the ball is pushed, then it will accelerate until the energy obtained from
the push reaches equilibrium with the drag and friction forces at which point
deceleration will occur because the energy of the ball begins to reduce while
the drag and friction forces are constant.
Variables:
Independent variable: The independent variable of this experiment is the
distance which the ball travels.
Dependent Variable: The dependent variable of the experiment is the time
taken for the ball to reach from point A to point B which in this case is from
one interval to the next. It is directly affected by the independent variable.
Controlled Variable: The controlled variables of the experiment would be the
ball (it must not be changed to ensure the test is fair), meter (some meters
have different ways of measuring and so to keep the data reliable, the same
meter must be used), stopwatch (like the ball, the stopwatch must be kept
the same to ensure the data is not bias).
Method:
1) Prepare the materials: a ball, a meter, a stop watch, cones.
2) Stretch the meter over the desired length, 30 m was used for this
experiment.
3) Place cones at 5 meter intervals along the meter.
4) Push the ball, as straight as possible.
5) Time the duration it takes to reach to each interval. It would helpful to
use a stopwatch with a lap function so that you do not interrupt the
ball’s course.
6) Record your results
7) Repeat steps 4-6 a few times to gather more data to make it more
precise.
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Safety precautions:
Basic safety precautions must be exercised when doing an experiment.
Equipment should be handled with care and students must behave sensibly.
Instructions must be followed and carried out. In this experiment there are
not many safety concerns as it is quite a basic experiment but the above
must still be followed. Students should not play with the ball or any of the
other equipment to make sure no harm comes to them or the apparatus.
Results:
Indp. variable
Distance (m)
5
10
15
20
25
30
Time (s)
T1
T2
0.17
1.85
2.13
2.63
3.10
4.71
1.81
0.73
0.98
1.04
1.30
1.55
Avg. Time (s)
0.99
1.29
1.56
1.84
2.20
3.13
Difference
between the
intervals
0.99
0.30
0.27
0.28
0.37
0.93
Measuring the speed of a ball at
certain intervals
3.50
3.00
Speed = 0.078x + 0.461
V = 0.926
Time (s)
2.50
2.00
1.50
1.00
0.50
0.00
0
5
10
15
20
Distance (m)
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25
30
35
Evaluation:
After examining the results it is evident that there is a strong relationship
between the speed of the ball in relation to the time and distance travelled.
As expected, the longer the time, the more distance is travelled by the ball.
It is clear, by looking at the table, that the same force was not used to push
the ball. This has resulted in slightly skewed results however the average of
both trials gives a more precise answer. By looking at the difference
between the intervals, it is apparent that the ball accelerated between the
intervals of 10m-20m and then decelerated due to opposing forces. The
equilibrium between the push force and the friction and drag forces clearly
occurs in the 15m mark. This means that at 15m, the ball had reached the
highest speed it could until being slowed down by opposing forces once
again. The method that was used for this experiment was very faulty. First,
we could not ensure that the ball was pushed with the same force twice.
Furthermore, we could not ensure that friction and air resistance would not
interfere with the experiment and slow the ball down. To have optimal
results that are reliable and fair, the experiment must be conducted in a
vacuum with zero gravity and the ball must be pushed by a machine to
ensure the same force is used to push the ball in every trial. This however is
impossible on earth, and in the environment provided, these are the most
accurate results available. The results were collected correctly as we used a
stopwatch with a ‘lap’ option and simply ‘lapped’ the time whenever the ball
passed a cone. Additionally, the speed of the ball depended on the ball itself
and the surface. A professional basketball was used in this experiment on a
rather rough surface covered in dust and small bits of dirt and debris.
Basketballs usually have bumps on their skin to give the handler a better
grip on the ball. If this experiment were to be repeated, a smoother ball
should be used and the floor should be cleaned so the friction is more
negligible.
Conclusion:
In conclusion, the aim of this experiment was achieved as we uncovered the
time it would take the ball to reach the different intervals. The results
showed that the ball accelerated due to the energy of the push and then
decelerated due to opposing forces. This means that once the initial energy
of the ball was exhausted, it relied on inertia to keep it moving but friction
and air resistance slowed the ball down.
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