If the common ratio of the sequence is between 0 and 1, then the term r would approach zero. When the ball collides with the floor, the ball becomes deformed. The coefficient of restitution is the ratio of the final to initial speed between two bodies after the collision. I do not believe that any ball will reach terminal velocity in this experiment seeing as the maximum height that they can be dropped from is 2m and, as the ball is quite smooth, I do not believe that it will have enough time to accelerate to its terminal velocity before it hits the floor. This denting extracts energy from the balls motion and stores much of it in the elastic surfaces of the floor and ball. 7. The reason for our error was that we thought that the tennis ball might be specially made to bounce to the same height. CR can be found out by looking at a graph, the gradient, as a percentage of 1 gives the amount of energy conserved and therefore CRcan be found without knowing v22or v12. ball bounced 6 inches. These equations allow us to predict how a change will affect the system without the need to do additional experiments. They identify variables to be changed, measured and controlled. Be perfectly prepared on time with an individual plan. will start at 2m and then move down in intervals of 10cm to 10cm. Measure the height the ball reaches after the first bounce and record. Possible sources of error include several types of measurement errors. After the ball reaches terminal velocity, no more GPE is converted into KE is the ball cannot get any faster. The mass of the ball will affect the height the ball bounces to because it affects the balls starting energy. Does a ball bounce higher or lower in moon (Less Gravity), while all other conditions are constant? WebThis experiment,is an investigation into the maximum height of the bounce of a ping pong ball when it is first released.This is because of the unpredictability of the bounce not always reaching the same height.This we can assume their are many factors effecting the bounce of the ping pong ball.The following experiment will determine how different = The distance between the bottom of the ball at the top of its arc after bouncing and the ground. 1. As the ball is falling toward the ground its Kinetic Energy is increasing because its speed is increasing. This means that the higher h. will differ from the height that the ball would have reached had it been dropped in a vacuum. In a real-life scenario, the ball will eventually stop moving due to external forces such as air friction. What is the control variable in the bouncing ball experiment? Find the infinite distance of travel. KE = 1/2mv where m = mass and v = velocity, 1/2mv = mhg - thermal energy (lost as a result of drag). Your bibliography must contain sources that are available to you (at your school or local library). This would mean that one could re-examine the height to which it bounced to and find it exactly instead of having to make a split second judgement which is not half as accurate. Based on these trends, we can draw conclusions about the system under study. You are now ready to enter your data on a spread sheet and get to work. This means that not all the GPE is converted into KE as it would have been if the ball had been dropped in a vacuum. Even a specific ball may bounce different heights at different times or different locations. Independent: - Type of surface the tennis ball is dropped on. Finally, we need to multiply the distance found by 2, as one bounce of the ball includes both a rise and fall. The coefficient of restitution is the ratio of the final to the initial relative speed between two objects after they collide. 15 inches, and the golf ball bounced 26 inches. This will hopefully discount any anomalies automatically and leave us with three accurate and reliable results. WebControl Variable: Simple Definition. Balls: Terminal Speed and Coefficient of Restitution. Everything you need for your studies in one place. External factors, i.e. For the lowest three points air resistance is approximately equal to zero due to the ball having a low velocity, as it was dropped from a low height, and therefore hits less air particles per second than a ball traveling at a faster speed. WebA control variable (or scientific constant) in scientific experimentation is an experimental element which is constant (controlled) and unchanged throughout the course of the The push which the ball receives from the floor at the moment of impact causes it to bounce up from the surface. Is a bouncing ball a simple harmonic motion? Either the coefficient to restitution that was worked out is incorrect, which would mean that the first three results are inaccurate or subsequent results were inaccurate. Method:The apparatus will be set up as shown: H is the height of the ball before it is dropped. Maybe you are reading a scale incorrectly, or maybe the measuring instrument is working erratically. 7. Advanced levels of experimental science rely heavily on graphical and mathematical analysis of data. Also the facts that there were no anomalies and that all of the points were very close to the line of best fit show that the experiment was relatively accurate. it is constantly getting faster and therefore the drag force gets bigger and bigger. Independent Variable: The height from which the ball is dropped. It will be vinyl tiling. As gravity remains the same the amount of work acting on the ball remains the same (apart from slightly more air resistance due to the ball travelling faster and so hitting more air particles per second, but the effect of this is negligible) and the ball travels further before stopping. Constants: the same person takes all of the measurements, the same materials are used in every trial. However if two results are recorded that do not fit the trend of other results nor are close to results recorded for that height then the experiments accuracy would be brought into doubt. The maximum and minimum results were included when working out the variation between results however, seeing as the maximum and minimum results were produced by the experiment and are therefore part of the variation between results produced by the experiment. The moving ball gains kinetic energy when it bounces, and loses potential energy as it falls. The results of our experiment show that this probably is not the case. The force that causes a ball to bounce is the reaction force described by Newton's third law of motion. The drag force increases as the ball goes faster. This is because it is easiest as the figure read of the meter rule is the result. Hence the final answer is: \(\text{Total distance} = 2 \cdot S_n = 2 \cdot 9.6 m= 19.2m\). When the ball was dropped from the higher heights the ball began to show signs of reaching its terminal velocity before it reaches the ground. You An increase in h1, assuming g and m stay constant, results in an increase in m g h1 which results in an increase in GPE. For a dropped ball, the total mechanical energy is defined as the sum of its kinetic energy and its gravitational potential energy. Lerne mit deinen Freunden und bleibe auf dem richtigen Kurs mit deinen persnlichen Lernstatistiken. or hold Ctrl and then use arrow keys to move the wave 0.01 second left or right. The CoR can be measured directly by velocity measurements but often it is handier to measure the height of rise of the ball after it bounces relative to the height that it fell. If you follow the motion of either ball, youll realize that theres a moment halfway through its bounce when the ball is perfectly motionless in contact with the floor. It is used to determine what the variable changed. Yes, as the ball is oscillating about the equilibrium position (in height) and goes back to its initial position after a period of time. The higher the ball goes, the more GPE it ends up with. This is impossible. A single experiment may contain many control variables. This would allow the actual coefficient to restitution to be calculated. WebBouncing balls. The ball has reached its terminal velocity and cannot fall any faster (unless dropped in a vacuum). A) Find the total distance of travel until the ball hits the ground for the 5th time. When you drop a ball from a greater height, it has more kinetic energy just before it hits the floor and stores more energy during the bounceit dents farther as it comes to a stop. Prediction reasons for variable control: The height the ball is dropped from will affect the height the ball bounces to due to the energy chain the ball goes through as it is dropped and bounces up again. If the coefficient to restitution = 0.7, a ball dropping from h1in a vacuum would reach the height of 0.7 h1 after bouncing. At that instant, how does the ball know how high it should bounce? The dependent variable is how high the ball bounces. Control variables include the type of ball, the surface that it is dropped onto and the size of the ball. 3. Testing reaction times can be investigated by dropping a ruler and seeing how quickly someone can grab it. The independent variable is the person who is trying to catch the ruler. Therefore of the GPE that the ball possessed at the beginning some energy is given off as thermal energy. Hypothesis: If a tennis ball is dropped from a specific height then the ball will bounce to the same height. The Graph on page 23 shows that all of the results were very close together. By the time it reaches the floor, the ball is traveling quickly and it hits the floor hard. The positive and negative directions must be stated in each example. As CR = h2/ h1it follows the gradient of the graph change in h2/ change in h1= CR. My hypothesis is based on my observation of balls that are not well inflated. At the terminal speed, the drag force = the gravitational force. When you hold a ball above a surface, the ball has potential energy. You will be able to precisely measure the time intervals between bounces. These polymers are tangled together and stretch upon impact. This will be a table tennis ball. So if we double the air pressure, we will get double bounce height. More thermal energy is also produced. The distance along the ramp which the balls rolls. Kinetic energy means energy associated with motion. WebAll experimental investigations involve variables. The more KE that the ball possessed as it hit the floor, the more that was transferred into elastic potential energy and back into KE. The experiment was conducted as the method (below) states. This list is called an experimental procedure. What type of motion does a bouncing ball experience? In this experiment the only variable that we modify is the type or flexibility of bounce surface and we keep all other variables unchanged. This did not happen in my experiment however. No, as the acceleration is not proportional to the displacement. Several new questions may have occurred to you while doing experiments. This will be called the average of the middle three repeats. If the ball is elastic in nature, the ball will quickly return to its original form and spring up from the floor. The ball pushes on the floor and the floor pushes back on the ball, causing it to rebound. Why? This would provide evidence on how the height from which the ball is dropped from affects the height to which it bounces without air resistance. The procedure allowed me to observe the affects of the height from which a table tennis ball was dropped from upon the height to which it bounced. Working out the variation in results shows how accurate the experiment was. Averages are more reliable than using one result as they take into account variation between results. h1and h2are from the bottom of the ball as it hits the floor to the bottom of the ball at the top of its arc after bouncing. Variables are B (81%) Synonyms. Try to find more information from physics or mechanics books. The energy chain is as follows: Therefore as energy cannot be created or destroyed the energy the ball starts with must be directly proportional to the energy the ball finishes with, at the top of its bounce, and so if the ball starts with more energy it must therefore finish with more. To set up the WebWhat is a control? As the height from which the ball was dropped from was increased, the GPE energy that the ball possessed before being dropped also increased. This would allow one to find the terminal velocity of the ball. Constants are the release height, the bouncing surface, the type and the size of the ball. The ball did not reach terminal velocity however as it did not have enough time to accelerate to its terminal velocity. This is because it is the easiest and quickest variable to alter. Therefore the results are valid. Air pressure will affect the balls fall slightly as the concentration of air particles per cubic meter varies with air pressure. Design an experiment to test each hypothesis. Often, mathematical equations can be made from graphs. Therefore the height the ball bounces will be proportional to the height that the ball is dropped from up to a certain point, where the ball begins to show signs of reaching its terminal velocity before it reaches the ground. As elasticity and hardness decreases, part of the ball energy will be used to permanently dent or misplace or vibrate the surface, so ball will have less energy to bounce. The controlled variables in this experiment are the surface the ball is rolling on, the material the ball is made of, the size of the ball, the measuring devices being used, the distance the ball travels, and the method being used to release the ball each time, for example the position of the hand. A ball falls from 8 metres and rebounds to 52 percent of its previous height. Bouncing Ball Experiment Our simple experiment is to drop a ping pong ball weighed at 3 grams from a height of 1 metre then 90cm, 80cm, 70cm, These both support my prediction and show that my prediction was correct. This slope tells us how bouncy the ball is. The ball moves upwards, reaching stage 1, i.e., maximum height, and its velocity is momentarily zero. Use two people to measure the results; one person to drop the ball and one to measure the height to which it reaches after bouncing. We felt the magic immediately.". If a ball reaches terminal velocity at 20cm from the floor when dropped from 2m, it will reach terminal velocity at 10cm from the floor when dropped from 1.9m. Tape the ruler to the wall. Therefore any change to the height from which the ball starts with affects the height to which it bounces to. The answer lies in how far the ball has dented inward due to its collision with the floor. Therefore the ball ends up with more GPE, , assuming g and m stay constant, results in an increase in m g h, , assuming g and m stay constant, results in a decrease in m g h, As the ball is accelerating due to gravity, at 9.81m/s. Repeat your tests 9 more times and each time lower the release height for 6 inches. Measuring the height to which the ball bounced on subsequent bounces would be interesting, seeing if h. It shows that heights were recorded that exceeded the height that the ball would have reached had it been dropped in a vacuum. The control variable is not part of an experiment itselfit is neither the independent nor dependent variable but it is important because it can have an effect on the results. Repeat this test from 2 ft, 3 ft, and 1/2 ft. Do this test for each ball and record data. Summary of task. So an imperfect ball loses some energy on each bounce. This means that if a heavier ball is to be used then it will need to be dropped from higher to reach its terminal velocity. The third stage is the point at which the ball is momentarily deformed, and bounces off the ground in an upward direction until it reaches its maximum height. If you are author or own the copyright of this book, please report to us by using this DMCA report form. Create and find flashcards in record time. The balls finish up with the same amount of energy and the only energy given out is thermal energy. Drop a ball from 1 foot off of the floor, slightly in front of a yardstick. The last term can be the lowest height of the ball before it comes to an end as seen below. Temperature will not affect the balls bounce either as the experiment will be conducted at room temperature, thus not allowing the floor to get cold and in doing so alter its affect upon the ball on impact. In this experiment you will drop a ball on a hard surface such as table and record the sounds it makes when it bounces using a computer and any sound recorder program. Course of Theoretical Physics : Mechanics (Course of Theoretical Physics), Engineering Mechanics Dynamics (11th Edition). Once the ball hits the ground, its displacement is momentarily zero. Writing Quality. Changes in the area of linoleum floor tile that the ball collided with may have affected the height to which it bounced to thus producing variation between results. Earn points, unlock badges and level up while studying. The motion of the ball can be described using velocity, displacement, and acceleration graphs, or geometric sequences. Your assistant will record the bounce. This project guide contains information that you need in order to start your project. WebA bouncing ball in an ideal scenario will continue this oscillatory motion. This would eliminate parallax error further. This motion can be described using a geometric sequence, as the height of the ball after each bounce depends on the initial height from which the ball fell. Here, the motion of a real bouncing ball is shown. For example a regulation tennis ball is dropped from about 1 meter. Therefore the coefficient to restitution = 0.7. It was decided that the first drop would start at 2m off the floor and then move down in intervals of 10cm to 10 cm off the floor. ", " My husband and son came with me for the tour. Therefore the ball dropped from the higher height must give out more thermal energy in order to end up with the same amount of energy as the other ball. These are parts of the experiment that you try to keep constant throughout an experiment so that they won't interfere with your test. The acceleration due to gravity causes the ball to change direction and start moving downwards at stage 2. \(Area = \frac{1}{2} \cdot base \cdot length\), \(Area = 0.5 m \cdot 50 m \cdot 50 m = 1250 m^3\). A control is a neutral reference point for comparison that allows you to see what changing a variable does by comparing it to not changing anything. In a real-life scenario, the ball will eventually stop moving due to external forces such as air. CoR = coefficient of restitution = (speed after collision)/(speed before collision). If the coefficient to restitution = 0.7, a ball dropping from h, in a vacuum would reach the height of 0.7 h, As velocity increases air resistance increases in proportion to the square of the velocity. The surface onto which the ball is dropped will affect the height to which the ball bounces because for any two objects that collide, the properties of both determine the percentage of the kinetic energy either possesses approaching the collision that is conserved subsequent to the collision taking place (Coefficient to restitution) discounting the effects of air resistance. 3. For each run, a different amount of change in the variable is used. The balls are shown at rest, about to bounce back up. You can drop the ball from your hand or you can make a stopper for the ball to hold it only from the sides with a little pressure. The material ball is made from will affect the ball as if it is smooth then the drag will be significantly less than if it is rough. For a falling object the Coefficient to restitution (CR) is equal to the velocity squared as the object is travelling at as it leaves the floor (v22) divided by the velocity squared as it hits the floor (v12): If dropping a ball in a vacuum all you need to know in order to know how high the ball will bounce to is h1 and CR. Studying tables and graphs, we can see trends that tell us how different variables cause our observations. Either the coefficient to restitution that was worked out is incorrect, which would mean that the first three results are inaccurate or subsequent results were inaccurate. GPE also changes as the ball falls. StudySmarter is commited to creating, free, high quality explainations, opening education to all. Therefore the height that it reaches is less high. List three. For testing air pressure you will need one ball that is inflatable such as a basketball ball. Is your hypothesis correct? Variables that may affect the bounce of a dropped ball are: You may study the effect of any of these variables on the bounce of a dropped ball. What principle describes the bouncing motion of a ball? This phenomenon is described by Newton's third law. Because the ball is softer than the floor, it does most of the denting and stores most of the energy. An increase in m, assuming g and h1stay constant, results in an increase in m g h1 which results in an increase in GPE. Once the drag force equals the gravitational force all forces are equal and acceleration stops. (Their ideas might include surface texture, colour, size, what its made of, squashiness, opacity, weight, air pockets, temperature, cost, shininess/dullness, hardness/softness, age, layers of materials.) Your assistant will record the bounce. Once the drag force equals the gravitational force all forces are equal and acceleration stops. Yes, as elastic potential energy causes the ball to bounce off the ground and is converted into kinetic energy once the ball is in the air, causing it to move. These inaccuracies could have been caused by external factors or parallax error even though efforts were made to avoid parallax error occurring - by dropping the ball one time that was not measured and placing a blob of blue tack onto the meter rule at the approximate height it bounced to. As the ball hits the floor with less KE than it would have done if it had been dropped in a vacuum it follows that less energy is converted into elastic potential energy and back into KE again. A control variable is any factor that is controlled or held constant during an experiment. It is also known as a constant variable or simply as a "control." Sign up to highlight and take notes. This means that the higher h1the more h2will differ from the height that the ball would have reached had it been dropped in a vacuum. Bounce/Release is the relation of bounce height to the release height. As the ball falls it hits against air particles. If the KE is the same as they hit the ground the energy stored in the ball as elastic potential energy will be the same also. Find out about the physics of a dropped ball. Hypothesis: Based on your gathered information, make an educated WebA) If a tennis ball is frozen, it won't bounce as high as one that is not frozen. These conclusions help us confirm or deny our original hypothesis. For instance, air resistance would slow down the tennis ball much more when it is dropped from 100 m than when dropped from 1 m. This difference in impact speed would probably affect the bounce height. As drag is a squared function, proportional to the square of the velocity, it is impossible to calculate the velocity that the ball hits the floor at. Find the total distance of travel until the ball hits the ground for the 8th time. The bounce of a dropped ball has a direct relation with the release height. If you are using windows sound recorder program, you can view the recorded waves with an accuracy of 0.01 second. The bouncing ball example is an example used to study, A bouncing ball in an ideal scenario will continue this oscillatory motion. Controlled: - Same ball. Also it shows inaccuracies in the experiment as it shows that heights were recorded that exceeded the height that the ball would have reached had it been dropped in a vacuum.
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