1) The document describes an experiment to determine the effect of different air pressures (psi levels) on the rebound height and velocity of a basketball. 2) The experiment involved dropping a basketball from a height of 2 meters and measuring its maximum rebound height using a meter stick and phone camera. The rebound height was then used to calculate rebound velocity through the conservation of energy equation. 3) The results showed a positive linear relationship between psi level and both rebound height and velocity, however the differences were small, with rebound height only increasing by 1.4% from 4.5 psi to 9 psi and velocity increasing by 0.7%. While the hypothesis was not supported, the experiment provided evidence

1. Submitted To
MS. Meherun Nesa
“ Lecture ”
Department of EEE
Green University Of Bangladesh
Submitted By
Group - 03
ID: 14, 18, 28, 37 , 61
Department of Textile
Green University Of Bangladesh
“ Effect of Pressure in Ball Bounce Height“
COURSE TITLE : Physic I Lab
COURSE CODE : PHY-102

2. ID : 201003018
ID
: 201003028
ID : 201003014
ID : 201003037
ID
: 201003061

3. Presentation Topic
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“Effect of Pressure in Ball Bounce Height“

4. To determine if different measures of PSI have a significant
effect on the initial rebound height and velocity of a basketball
.
To analysis the ball bounces back up more significantly than psi
levels

5. Learning Outcome
Understanding enhence knowledge about how
dose air pressure in a ball make the ball bounce
higher
Able to understood the physics of bouncing balls
Undesrtanding energy with a bouncing ball .

6. When a basketball is inflated, it is being inserted with lots of air, similar to that of a balloon.
The basic principle is that when more air is pushed into the ball, the air pressure increases
because the air is being squished, trying to fit in a minimal space. As the air becomes
more compact, it then pushes against itself in the ball, therefore having a force which is
called air pressure this force is what inflates the ball into the sphere shape. When the
basketball makes contact on the ground, we are temporally pressing on the ball which
squishes the air even more. The importance of this is since the ball is compact with air, the
air then presses back with a certain force. This certain force is the cause to the rebound of
the ball; thus, indicating that as higher pressures are applied, the ball will bounce higher.
The force which the ball exerts is then followed by a velocity, and is also in the same
relationship . Rebound, in a sports context, is when a ball bounces back from striking a
hard surface or object. In this case, rebound is a significant factor, especially to those who
play basketball, because it can determine the height when a basketball is dropped or
dribbled on the court. However, a basketball rebound is dependent on the amounts of
pressure inserted into the ball per inch.
Theory

7. Materials Required/ Apparatus
Meter stick
Standard Indoor Leather basketball (75 cm
circumference)
Pressure Gauge Barometer
Recording device (preferably with the slow down option)
Ladder

8. Specification of Components
A meterstick or yardstick is either a straightedge or foldable ruler
used to measure length, and is especially common in the
construction industry. They are often made of wood or plastic,
and often have metal or plastic joints so that they can be folded
together.
High quality basketballs are made of genuine leather or
composite leather (cheap balls are made of rubber). Balls that
are made of genuine leather are generally considered to be the
best ones and are used in the NBA and WNBA. They are also
the most expensive type of balls

9. A meterstick or yardstick is either a straightedge or foldable
ruler used to measure length, and is especially common in the
construction industry. They are often made of wood or plastic,
and often have metal or plastic joints so that they can be
folded together.
For recoding we need a good recoding device . So we
used Tecno camon 16 . This phone have a very good
quality slow motion recording option with countinuous slow
motion shooting in HD quality at 960 frames per second .
A piece of equipment consisting of a series of bars or
steps between two upright lengths of wood, metal, or
rope, used for climbing up or down something.

10. Procedure
Ball selection : An indoor basketball was utilized for the
experiment. The same 75.0 centimeter circumference ball was
conducted in all six trials for each psi levels. Although it is true that
certain materials on the surface of the ball could result in different
impacts and various forces, the standard indoor leather wrapping ball
was used. The same area point on the ball was dropped as well to
further reduce any possible procedural errors.
Drop height : Every basketball in all psi levels were dropped from
the same height of 2.0 meters. This value does not play a role in any of
the calculations, but is valuable to provide a uniform height for each
level.

11. This will be calculated from the initial
bounce for each psi level. The average will be taken and it
will then be inserted into a graph to determine the
significance of the slope. An iphone with the slow motion
option will be used to measure the height once it bounces.
The average height recorded will then
be plugged into an energy conservation equation to
determine the rate of the velocity applied at all psi levels.
After finding the velocity, the data will be in the form of a
graph to determine the significance of the slope.

13. • The dependent variable was the basketball rebound height, h, which is
measured at the maximum initial rebound in meters. To measure h, a meter stick
was aligned to the wall. When the ball is dropped from the height of 2.0m and
bounces back up, a phone will record the maximum height it reaches.
• The independent variable are the various levels of psi: 4.5, 5.0, 5.5, 6.0, 6.5, 7.0,
7.5, 8.0, 8.5, 9.0. A higher domain would burst the basketball as basketball air
pressure has a limit just like that of a balloon. A lower domain would result in no
initial bounce, which would not pair well with the results.
• The control variable is the standard 8.0 psi level for an indoor basketball. This
psi is crucial as it will be compared to every psi above and below it to dispose
the significance of the relationship between psi and height/velocity
Experimental Variables

14. • Controlled variables consist of: A controlled environment will
be used to conduct the experiment, ensuring no wind factor,
humidity, and temperature factor. Additionally, the scientific
equipment will be calibrated in order to check if it is working
and producing accurate outcomes with correct
measurements. The basketball was dropped from the same
surface at the same area. Any offset values or outliers were
removed from the data collection and was redone for that
trial; doing so would allow proper analysis and conclusions
based on the results rather than on defective outcomes. This
is a good scientific practice, demonstrating the effects of
nature and procedural errors on the science at work.

15. PSI 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 8.5 9.0
Trail 1 1.258 1.308 1.354 1.397 1.427 1.461 1.483 1.499 1.509 1.511
Trail 2 1.301 1.303 1.361 1387 1.411 1.473 1.472 1.486 1.509 1.524
Trail 3 1.297 1.306 1.326 1.405 1.410 1.468 1.479 1.506 1.510 1.522
Trail 4 1.279 1.303 1,347 1.401 1.415 1.463 1.481 1.502 1.507 1.515
Trail 5 1.263 1.310 1.315 1.390 1.423 1.470 1.476 1.498 1.511 1.520
Trail 6 1.280 1.315 1.359 1.405 1.410 1.468 1.472 1.496 1.508 1.519
Mean 1.281 1.307 1.350 1.397 1.416 1.467 1.477 1.497 1.509 1.518
Observations

16. Graph 1 shows the linear growth with its equation and r2 value. This graph indicates that as
the psi increases, the height in meters rises slightly, but not as significantly as predicted. As seen from
the data table and the graph above, at 4.5 psi, it was at 1.281 meters. But at 9.0 psi, the height was
1.518 meters. A difference of .237 meters was shown. The r2 value is high (0.95446), indicating a low
dispersion of data around the best fit line. Having this strong line suggest that the effects of psi on the
initial rebound height is valid.

17. mgh = (1/2) mv^2
m is mass, g is gravity, h is height, and v is velocity.
For example, at psi of 4.5, the calculations is as follows.
(9.81ms^-2) (1.281)= (1/2) (v^2)
[The mass cancels from both sides]
v(4.5) = 5.013 ms^-1
Velocity Calculations :
After acquiring the average height for each psi, it was then plugged into
a conservation of energy equation to determine the rate of velocity it
was moving between the ground to the air. This formula below will be
used:

18. As Like
v(5.0) = 5.063 v(5.5) = 5.146 v(6.0) = 5.235
v(6.5) = 5.270 v(7.0) = 5.364
v(8.0) = 5.419
v(7.5) = 5.383
v(8.5) = 5.441 v(9.0) = 5.457
PSI 4.5 5.0 5.5. 6.0 6.5 7.0 7.5 8.0 8.5 9.0
Velocity
(ms^-1)
5.146 5.063 5.146 5.235 5.270 5.364 5.383 5.419 5.441 5.457

19. Graph 2 also indicates a linear growth in velocity. The r2 value is high (0.95015), suggesting
that the dispersion of data is not far from the best fit line. This reveals how psi does have an
effect on rebound velocity, but not significantly because the difference between the highest
(9.0 psi) to (4.5 psi) was only .444 ms-1 apart. Error bars were not needed here because the
velocity was only calculated by a formula, not recorded by the camera.

20. Conclusion
The hypothesis was not supported. It was predicted in the hypothesis
that at 9.0 psi, it would reach 10% of a greater height and velocity than
the 8.0 psi (control), and at 4.5 psi, it would decrease at 20%. At 9.0 psi,
the height only increased by 1.4% and the velocity by 0.7%. At 4.5 psi, it
only decreased at a height by 14.4% and the velocity by 7.5%. Despite the
previous mentioned limitations and unsupported hypothesis, the
research question was in fact partially supported. The effects of psi on
rebound height in graph 1 was not significant, but the positive linear
slope suggest that the effects were prominent. Clearly, having a higher
pressure does result in a larger force, supporting the methodology that
psi contributes to greater rebound in both height and velocity.