2021 Live Review 6 | AP Physics 1 | Understanding Simple Harmonic Motion

The speaker, Joshua Beck, begins by addressing the audience and acknowledging the feedback received through a form. He appreciates the audience's engagement and assures them that their voices are heard. He then introduces the topic of the day, which is simple harmonic motion, and mentions that he will also cover experimental design based on the audience's request. Beck provides an overview of what simple harmonic motion is, describing it as an oscillation between two positions with a maximum displacement known as amplitude. He explains the concepts of frequency and period, using a visual aid to illustrate the motion and how it can be represented graphically. Beck emphasizes the importance of understanding the underlying forces and requirements for an object to oscillate in simple harmonic motion, using a spring as an example to demonstrate how the force changes in response to displacement.

Continuing the discussion on simple harmonic motion, Beck delves into the specifics of force and acceleration within this context. He clarifies that the force experienced by an object in simple harmonic motion is proportional to its displacement and changes direction as the object moves. Beck uses an experiment with two springs and a mass to illustrate that the frequency of oscillation remains constant despite different masses and spring constants. He further explains the relationship between force and position, and how it can be visualized graphically. Beck also touches on the concepts of maximum acceleration and velocity, and where these occur in the oscillation cycle. He emphasizes the importance of understanding that force is not constant and varies as the object moves through its cycle.

In this section, Beck focuses on the graphical representation of simple harmonic motion, specifically discussing the relationship between force, position, velocity, and acceleration. He uses a video and force sensor data to demonstrate how these quantities change over time and position. Beck highlights the maximum and minimum values of force, velocity, and acceleration and explains when these occur during the oscillation. He also discusses the concept of energy in the context of simple harmonic motion, differentiating between kinetic and potential energy. Beck encourages the audience to make predictions about how changes in mass and spring constant affect the period of oscillation, and then confirms these predictions with experimental data.

Beck shifts the focus to experimental design, aiming to determine the spring constant (k) of an ideal spring. He outlines three possible approaches: force analysis, energy analysis, and oscillation analysis. Beck decides to concentrate on the oscillation aspect, using the period of oscillation as a means to find k. He explains the mathematical relationship between the period, mass, and spring constant, and how this can be rearranged to solve for k. Beck then describes a step-by-step procedure for conducting the experiment, including the selection of equipment, collection of data, and the process of graphing and analyzing the results to find the spring constant. He emphasizes the importance of collecting multiple data points and the process of linearizing the data to find a straight line, which allows for an accurate calculation of k.

Beck explores the effects of changing the mass and spring constant on the period of oscillation in a mass-spring system. He uses the previously established formula for the period and applies the concept of the factor of change to demonstrate how doubling the spring constant would affect the period. Beck then explains how to maintain the same period if the spring constant is changed, by adjusting the mass accordingly. He further discusses what would happen if both the mass and spring constant are altered simultaneously, using the same factor of change approach. Beck's explanation helps to clarify how these variables interact and influence the period of a mass-spring oscillator.

In the concluding part of the video, Beck summarizes the key points discussed in the session and encourages the audience to utilize the available resources for further study and clarification. He mentions the AP daily videos and specific unit videos that could be beneficial for those needing extra help with experimental design and equipment selection. Beck also informs the audience about the location of the workbook within the AP classroom and reassures them that their feedback is valued and being reviewed, even though there is no direct method for responding. He signs off, reminding viewers about the next session with Kristin and encourages them to continue engaging and learning.