The Bouncing Ball Lab- Loss of Energy

[prestonubc22]

1. Okay. So, my lab is to bounce a ball at a given high while i calculate the time, mass, and different heights. Given these I find the PE, Velocity, and Difference in PE. I've gotten most of the lab complete but there is a final question that asks "If you wanted the golf ball to rebound to a height of 3ft, which was the tested initial height, how high in units of ft would the golf ball need to be initially placed before released.
2. There is also a question that asks: "Calculate the difference in PE in J between the initial height and rebound height, and explain what happened to account for the loss of height in terms of conservation of energy?" I understand how to find the difference the PE from the initial height and the PE after it was rebounded but what does she mean by the conservation of energy thing?



3. For the golf ball I have an initial height of .91m, a PE of .4 J, a velocity of 2.33 m/s, avg rebound height of .56m w/ a PE of .25 J, and the difference is .15 J.



4. I am not sure where to start, really. I thought of possibly doing .4J/.25J and plugging that into PE=mgH but I'm not sure if that'd give me the answer. If anyone could please help me that'd be great. This paper is due at 8am tomorrow morning. Thanks!
Additional info: M=45g Initial height 1 yd travel time: .39sec.

 

[mfb]

8am in which time zone? ;)

I thought of possibly doing .4J/.25J and plugging that into PE=mgH

You cannot use a ratio as an energy value.
You can assume that this ratio is the same for each bounce (it won't be, but it is a good approximation). What was the fraction of energy lost you observed? If it is the same for every bounce, ...

but what does she mean by the conservation of energy thing?

Did you hear of conservation of energy? You start with .4J and end up with .25J, could this be an issue?

 

[prestonubc22]

8am in which time zone? ;)

You cannot use a ratio as an energy value.
You can assume that this ratio is the same for each bounce (it won't be, but it is a good approximation). What was the fraction of energy lost you observed? If it is the same for every bounce, ...

Did you hear of conservation of energy? You start with .4J and end up with .25J, could this be an issue?

Sorry, Eastern Time Zone. Clemson, SC. Well what i did was (.045kg)(9.8m/s^s)(.91)=.40 kgm^s/s^s=.40J Then, (.045kg)(9.8m/s^2)(.56m)= .25J. So, .40J-.25J= .15J. And, i understand that the energy lost will not be the same, as the heights will be different with every bounce due to the loss of energy. I just can't seem to figure out the initial height. Any hints you can give me? I'm really stuck..

 

[mfb]

All of my previous post is a collection of hints how to proceed...

 

[HalfLostAndSearching]

I would like to first commend you on completing most of the lab and gathering important data such as time, mass, and heights. It is important to always gather accurate data in order to draw meaningful conclusions.

To answer the first question, in order for the golf ball to rebound to a height of 3ft (0.91m), it would need to be initially placed at a height of 1 yard (0.91m) before being released. This is because in order for an object to rebound to a certain height, it needs to have an initial potential energy equal to or greater than the potential energy at the desired rebound height.

For the second question, the conservation of energy refers to the principle that energy cannot be created or destroyed, only transferred from one form to another. In the case of the bouncing ball, the initial potential energy (PE) is converted into kinetic energy (KE) as the ball falls, and then back into potential energy as it rebounds. However, due to factors such as air resistance and friction, some of the initial potential energy is lost and cannot be converted back into potential energy during the rebound. This results in a decrease in rebound height and a difference in potential energy between the initial and rebound heights.

To calculate the difference in potential energy, you can use the formula PE = mgh, where m is the mass, g is the acceleration due to gravity, and h is the height. In this case, you can subtract the initial potential energy (PE) from the potential energy at the rebound height to find the difference in potential energy lost. This difference in potential energy can be explained by the loss of energy due to air resistance and friction.

In terms of your additional information, it is important to use consistent units when calculating and comparing values. You have provided the initial height in meters, but the travel time in seconds and the mass in grams. It would be helpful to convert all units to either meters or yards to ensure accuracy in your calculations.

In conclusion, it is important to consider the principles of energy conservation when analyzing the results of your bouncing ball lab. By understanding the concept of energy conversion and loss, you can better explain the difference in potential energy and the decrease in rebound height. I hope this explanation helps and good luck with your paper.