1553268228829_effect Of Presure In Ball Bounce Height 2.docx

EFFECT OF PRESURE IN BALL BOUNCE HEIGHT Project report submitted to Kannur University in partial fulfillment of the requirement for the award of Degree OF Bachelor of Science in Physics

Submitted by ABHISHEK KRISHNAN M Reg.No. PP16CPHR38 PAYYANUR COLLEGE

PG and Research Department of Physics Payyanur College March 2019

DECLARATION

I, ABHISHEK KRISHNAN M , hereby declare that the project work entitled ‘EFFECT OF PRESSURE IN BALL BOUNCE HEIGHT ‘ submitted to Kannur Universiy in partial fulfillment of reqirement for the award of Bachelor of Science in Physics is record of original work done by me under the supervision of Sri. Sreejith E K , Assistant Professor , Department of Physics , Payyanur College.

I also declare that this project work has not been submitted to me fully or partly for the award of any other Degree,Diploma , Title or recognition before any other authority.

ABHISHEK KRISHNAN M BSc.Physcs Reg.No: PP16CPHR38 Payyanur College

CERTIFICATE

This is to certify that the project work entitled ‘ EFFECT OF PRESSURE OF BALL BOUNCE HEIGHT ‘ has been carried out by ABHISHEK KRISHNAN M under my supervision in partial fulfillment of the requirement for the award of Degree of Bachelor Science in Physics of Kannur University.

Smt.PREETHI RAJAN

Sri. SREEJITH E K

Associate Professor

Assistant Professor

Head of the Department

Supervising Guide

Department of Physics

Department of Physics

ACKNOWLEDGEMENT I present my whole hearted compliments with high regards and warm thanks to one and all, who supported me in this project . With immense pleasure and heartiest gratitude , I express my sincere thanks to my guide in charge , SREEJITH E K for valuable suggestions and guidance. I would like to express my gratitude towards all the faculty members , teaching and nonteaching staffs and classmates fo their support.

CONTENT 1. 2. 3. 4. 5. 6. 7. 8.

INTRODUCTION OBJECTIVE MATERIALS REQUIRED PROCEDURE EXPERIMENTAL VARIABLES OBSERVATIONS VELOCITY CALCULATIONS CONCLUSION

1.INTRODUCTION While watching Basketball games , it was always my interest as to know why referees would examine the basketball. The basketballs were fully pumped to my awareness, but I noticed referee checking the air pressure using a psi barometer. Later I found that the standard indoor basketball pressure is 8.0 psi . From then, I was curious as to know why basketball games have this psi regulation. What would the significance if it were to be slightly high- or vice versa ? Would the speed n which the ball bounces back from the ground increase if the psi was raised ? These are the questions which motivated me to answer through this investigation.

2.OBJECTIVE The purpose of this investigation is to determine if different measures of psi have a significanteffect o yhe initial rebound height and velocity of a basketball. If a basketball with a circumference of 75.0 cm, were inserted with a psi’s of 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0 and was dropped from a height of 2.0 metres, then the psi at 9.0 would inflict a higher rebound height and velocity when compared to other psi value. This is because the extra air pressure pushes against the bottom of the ball, making it push harder against the ground which leads to the ground pushing back equally hard. Therefor, the ball bounces back up more significantly.

3.MATERIALS REQUIRED  Meter stick  Standard Indoor Leather basketball ( 75cm circumference )  Pressure Gauge Barometer  Recording Device  Ladder (Optional)



BASKETBALL (BALL)

A basketball is a spherical ball used in basketball games. Aside from the court and the baskets, the basketball is the only piece of equipment necessary to play the game of basketball. During the game, the ball must be bounced continuously (dribbling), thrown through the air to other players (passing) or thrown towards the basket (shooting). Therefore, the ball must be very durable and easy to hold on to. The ball is also used to perform tricks (sometimes called freestyling), the most common of which are spinning the ball on the tip of one's index finger, dribbling in complex patterns, rolling the ball over one's shoulder, or performing aerobatic maneuvers with the ball while executing a slam dunk, most notably in the context of a slam dunk contest. Nearly all basketballs have an inflatable inner rubber bladder, generally wrapped in layers of fiber and then covered with a surface made either from leather (traditional), rubber, or a synthetic composite. As in most inflatable balls, there is a small opening that allows the pressure to be increased or decreased.



PRESSURE GAUGE BAROMETER

A barometer is a scientific instrument used to measure air pressure. The pound per square inch or, more accurately, pound-force per square inch (psi) is a unit of pressure or of stress based on avoirdupois units. It is the pressure resulting from a force of one pound-force applied to an area of one square inch. In SI units, 1 psi is approximately equal to 6895 N/m2

4.PROCEDURE  Ball selection : An indoor basketball was utilized for the experiment . The same 75.0 centimeter circumference ball was conduced in all six trials for each psi levels. Although it is true hat certain materials on the surface of the ball could result in different impact 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 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 it is valuable to provide a uniform height for each level.

 Rebound height : 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 significance of the slope .

 Rebound Velocity : The average height recorded will be ten be plugged into an energy conservation equation to determine the rate of the velocity applied at all psi level. After finding the velocity, the data will be in the form of a graph to determine the significance of the slope.

5.EXPERIMENTAL VARIABLES

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 bounce back up, a phone will record the maximum height it reaches.

The independent variable are the various levels of psi 4.4, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0.

6. OBSERVATIONS Effect of PSI on rebound height measurement in meters . PSI Trial 1 Trial 2 Trial 3 Trial 4 Trial 5 Trial 6 Mean

4.5

5.0

5.5

6.0

6.5

7.0

7.5

8.0

8.5

9.0

1.258 1.308

1.354

1.397

1.427

1.461

1.483

1.499

1.509

1.511

1.301 1.303

1.361

1.387

1.411

1.473

1.472

1.486

1.509

1.524

1.297 1.306

1.326

1.405

1.410

1.468

1.479

1.506

1.510

1.522

1.279 1.303

1.347

1.401

1.415

1.463

1.481

1.502

1.507

1.515

1.263 1.310

1.351 1.390

1.423

1.470

1.476

1.494

1.511

1.520

1.28

1.315

1.359

1.405

1.410

1.468

1.472

1.496

1.508

1.519

1.281 1.307

1.350

1.397

1.416

1.467

1.477

1.497

1.509

1.518

This graph indicates that as the psi increases, the height in meters rises slightly, but not as significantly. As een from the data table and graph , at 4.5 psi, it was at 1.281 meters. But at 9.0 psi, the height was 1.518 meters. A difference of 0.237 meters was shown.

Effect of PSI on initial rebound height

10 9 8 7 6 PSI

5 4

Y-Values

3 2 1 0

1.25

1.3

1.35

1.4

1.45

Height in meters

1.5

1.55

7. 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 will be used: mgh = (1/2)mv^2 m is mass, g is gravity, h is height, and v is velocity.

mgh = (1/2)mv^2 gh = (1/2)v^2 v ^2 = 2* 9.8*1.281 v(4.5) = 5.0107 m/s

PSI

4.5

5.0

5.5

6.0

6.5

7.0

7.5

8.0

8.5

9.0

Rebound velocity 5.0107 5.0613 5.1439 5.2327 5.2681 5.3622 5.3804 5.4167 5.4384 5.45 46

h 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

herThis

graph also indicates a linear growth in velocity. This reveals how psi does have an effect on rebound velocity, but no significantly because the difference between the highest (9.0 psi) to (4.5 psi ) was only 0.444 m/s apart.

Effect of PSI on initial rebound velocity 10 9 8 7 6 5

PSI

4

Y-Values

3 2 1 0 4.9

5

5.1

5.2

Velocity in meters per second (m/s)

5.3

5.4

5.5

8. CONCLUSION

Overall, I was amazed that my data could justify why an 8.0 psi is logical to be the standard pressure amount. Although the difference at 9.0 psi and 4.5 psi was not as significant as I would have thought it would be, the slight change in velocity and rebound height from these two psi levels could indeed impact a lot of players since the anticipated velocity and height would be much faster or slower. Having all basketballs regulated at 8.0 psi provides a uniform rate.

BIBILOGRAPHY  “ Do Basketballs that are fully inflated Bounce better than Flatter ones ? “ USCB Science Line, scienceline.ucsb.edu/getkey.php?key=3939.  www.wikipedia.com