Hello, I need some clarification with my lab report

[Soni12652890]

Homework Statement

Would it be possible for someone to look over the parts of my lab report. If there is anything that I did not mention in the abstract, please inform me. I wasn't sure how I should end the paragraph. My teacher wants us to write our opinion on the success of the experiment (supported by results) but I am still confused about some of the questions. Specifically, I need help with calculating the percent of energy lost in the system.

Homework Equations

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The Attempt at a Solution

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In a homework problem, I understood that kinetic energy is transferred to potential energy with rotational momentum conserved and that from that height can be derived. I don't know how to find that kinetic energy for the pendulum. I know that to find initial kinetic energy, I add the kinetic energy of both objects (1/2 mv^2) and to find final kinetic energy, I would use the final velocity of the mass (1/2(m1 + m2) * Vfinal = Kfinal. However, I don't believe that the same formula is used to find the potential energy for the experiment.
Thank you
-M.S

 

[andrevdh]

For the pendulum you assume that the kinetic energy at the bottom (just after it caught the ball and the ball came to rest in the cradle) is converted to the potential energy at the top of the swing.

 

[Soni12652890]

Thank you for replying.
I understand that I can set the kinetic energy at the bottom to the potential energy at the swing but I would need to use
K(initial) = 1/2 (mass of ball + Mass of pendulum) * v^2(initial)
K(final) = (mass of ball + Mass of pendulum) * 9.81 * height ?

How can I use the height that was calculated with the initial speed of the ball. I have the velocity of the ball as it is released, but then I have the kinetic energy. Then I set that equal to the kinetic energy of the pendulum and the ball.
1/2(mass of ball) * velocity of ball^2 = 1/2(mass of ball + mass of pendulum) * velocity of both objects^2
I found find the velocity of both the objects and then set it equal to the potential energy to find the height?

 

[andrevdh]

The K_i would not include the mass of the pendulum since it is initilally stationary isn't it?
Can't you calculate the height with the angle and length of the pendulum?
The percentage lost would then be ΔK/K_i x 100

 

[HalfLostAndSearching]

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Dear M.S.,

Thank you for reaching out for clarification on your lab report. It is always a good idea to have someone review your work and provide feedback. Regarding your question about the end of your paragraph, it is important to write a conclusion that summarizes the main findings of your experiment. This includes your opinion on the success of the experiment, supported by your results. As for calculating the percentage of energy lost in the system, it is important to first understand the concepts and equations involved. In this case, you would need to calculate the initial and final kinetic and potential energies for the pendulum. The formula for potential energy is mgh, where m is the mass, g is the acceleration due to gravity, and h is the height. Once you have these values, you can use the equation (Kinitial - Kfinal) / Kinitial to calculate the percentage of energy lost. I hope this helps clarify your confusion. Please let me know if you have any further questions.

Best,