AP Physics 1 Kinematics Problem #3

Allen Tsao The STEM Coach
4 Oct 201809:07
EducationalLearning
32 Likes 10 Comments

TLDRIn this video, Alan from Bothell STEM guides viewers through an AP Physics experiment to determine gravitational acceleration using a falling steel sphere. He explains how to plot data points and derive a linear relationship by graphing distance against half the square of time. Alan also discusses potential improvements for increased accuracy.

Takeaways
  • πŸ“š The video is an educational tutorial by Alan from Bothell STEM, focusing on AP Physics kinematics problems.
  • πŸ” The tutorial is based on an AP Physics B exam question, which is useful for practice even for AP Physics 1 students.
  • πŸ§ͺ The problem involves designing an experiment to determine the acceleration due to gravity using a steel sphere and a recording plate.
  • πŸ“ˆ The student is expected to plot data points and sketch a curve that represents the relationship between the distance fallen and the time taken.
  • πŸ“‰ The key to solving the problem is to find a linear relationship using the variables distance (D) and time (T).
  • πŸ“ The kinematic equation used is D = 1/2 * G * T^2, where G is the acceleration due to gravity and T is the time.
  • πŸ“ To find a linear relationship, the student should plot D against (1/2 * T^2), which will yield a slope equal to G.
  • πŸ“Š The video includes a demonstration of plotting the data points and calculating values for (1/2 * T^2).
  • πŸ“ The slope of the line in the graph of D versus (1/2 * T^2) is used to estimate the value of G.
  • πŸ” The video discusses potential inaccuracies in the experiment and suggests increasing the distances to improve accuracy.
  • 🌐 Alan offers free homework help on platforms like Twitch or Discord for those with questions in math and physics.
Q & A
  • What is the main objective of the experiment described in the video?

    -The main objective of the experiment is to determine the acceleration due to gravity (G) using a small steel sphere and a recording plate.

  • What apparatus is used in the experiment to measure the acceleration due to gravity?

    -The apparatus used includes a device that holds a small steel sphere above a recording plate. When the sphere is released, a timer automatically starts and stops when the sphere strikes the recording plate.

  • How does the timer in the experiment work?

    -The timer automatically begins recording the time of fall when the sphere is released and stops when the sphere strikes the recording plate.

  • What data is recorded in the experiment and how is it used?

    -The student measures the distance of the fall (D) for different values and records the data in a table. This data is then plotted on a graph to determine the relationship between distance and time.

  • Why is it important to sketch a smooth curve on the graph?

    -Sketching a smooth curve on the graph helps in analyzing the data and understanding the relationship between distance (D) and time (T), which is crucial for determining the acceleration due to gravity.

  • What kinematic equation is used to relate distance, initial velocity, acceleration, and time?

    -The kinematic equation used is \( \Delta x = v_0 t + \frac{1}{2} a t^2 \), where \( \Delta x \) is the distance, \( v_0 \) is the initial velocity, \( a \) is the acceleration, and \( t \) is the time.

  • Why is the initial velocity (v0) considered zero in this experiment?

    -The initial velocity is considered zero because the sphere is dropped from rest, meaning it has no initial horizontal or vertical velocity before being released.

  • How can the acceleration due to gravity (G) be determined from the data?

    -The acceleration due to gravity (G) can be determined by plotting the distance (D) versus \( \frac{1}{2} T^2 \) and finding the slope of the resulting graph, which represents the value of G.

  • What is the significance of plotting D versus \( \frac{1}{2} T^2 \) to produce a linear relationship?

    -Plotting D versus \( \frac{1}{2} T^2 \) produces a linear relationship because the equation \( D = \frac{1}{2} G T^2 \) simplifies to a linear form, making it easier to determine the slope (G) directly.

  • How can the accuracy of the experiment be improved?

    -The accuracy of the experiment can be improved by increasing the distances and measuring more time values, which would provide more data points for a more reliable linear fit.

Outlines
00:00
πŸ“š AP Physics Kinematics Experiment Design

In this segment, Alan from Bothell STEM introduces an AP Physics kinematics experiment designed to determine the acceleration due to gravity (G). Using a setup that involves a small steel sphere falling onto a recording plate, time is measured for different distances (D). Data points are plotted on a graph, and the student is tasked with sketching a curve that represents this data. The key to finding G lies in creating a linear relationship using the variables D and T (time). Alan suggests plotting D against 1/2 T squared, which, according to the kinematic equation Ξ”X = 1/2 GT^2, should yield a straight line with G as the slope. The summary includes a step-by-step guide on how to calculate and plot the necessary values, emphasizing the importance of accuracy in measurements.

05:01
πŸ“‰ Analyzing the Experimental Data for Gravity's Acceleration

Alan continues the discussion by focusing on the analysis of the experimental data to find the acceleration due to gravity. He explains the process of plotting the values of D against 1/2 T squared on a graph and attempts to draw a line of best fit. The slope of this line represents the acceleration due to gravity. Alan calculates the slope using two points on the graph and finds it to be approximately 10 m/s^2, acknowledging that it deviates from the expected 9.8 m/s^2. He suggests ways to improve the accuracy of the experiment, such as increasing the distances and ensuring more precise measurements. The summary concludes with Alan offering free homework help on Twitch or Discord for those interested in further learning or assistance with math and physics.

Mindmap
Keywords
πŸ’‘AP Physics
AP Physics refers to the Advanced Placement Physics courses offered by the College Board, which are designed to provide high school students with college-level physics education. In the video, the instructor is discussing AP Physics 1, which is a course that covers topics such as kinematics, dynamics, and energy. The video script mentions 'AP Physics B' and 'AP Physics 1', indicating that the content is relevant to these courses.
πŸ’‘Kinematics
Kinematics is a branch of physics that deals with the motion of objects without considering the forces that cause the motion. It focuses on the description of motion in terms of displacement, velocity, and acceleration. In the video, the instructor is discussing problems related to kinematics, specifically the motion of a falling steel sphere and how to determine acceleration due to gravity.
πŸ’‘Acceleration due to gravity
Acceleration due to gravity, often denoted as 'g', is the acceleration that an object experiences due to the gravitational force of the Earth. It is approximately 9.8 m/sΒ² near the Earth's surface. The video script involves an experiment to determine the value of 'g' by measuring the time it takes for a steel sphere to fall a certain distance.
πŸ’‘Experimental design
Experimental design is the process of planning and conducting experiments to test a hypothesis or to collect data. In the video, the instructor discusses an experimental design problem where a student is tasked with determining the acceleration due to gravity using a setup that involves a steel sphere, a recording plate, and a timer.
πŸ’‘Recording plate
A recording plate is a device used in the experiment described in the video to record the time when a falling object strikes it. The timer automatically starts when the sphere is released and stops when it hits the recording plate, allowing the measurement of the time of fall.
πŸ’‘Data points
Data points are individual measurements or observations that are collected during an experiment. In the video, the instructor refers to data points that are plotted on a graph to determine the relationship between the distance fallen (D) and the time taken (T). These data points are crucial for analyzing the motion of the steel sphere.
πŸ’‘Graph
A graph is a visual representation of data, often used to show relationships between variables. In the video, the instructor discusses plotting data points on a graph to analyze the motion of the steel sphere and to determine the acceleration due to gravity. The graph helps visualize the quadratic relationship between distance and time.
πŸ’‘Quadratic relationship
A quadratic relationship is a type of mathematical relationship where one variable is proportional to the square of another variable. In the video, the instructor identifies a quadratic relationship between the distance fallen (D) and the time taken (T), which is used to derive the acceleration due to gravity.
πŸ’‘Initial velocity
Initial velocity is the velocity of an object at the start of its motion. In the context of the video, the steel sphere is released from rest, so its initial velocity is zero. This is important in the kinematic equations used to analyze the motion of the sphere.
πŸ’‘Free homework help
Free homework help refers to the offer made by the instructor in the video to provide assistance with homework questions or to learn about different parts of math and physics. This is an additional service offered by the instructor, suggesting a community or platform (like Twitch or Discord) where students can seek help.
πŸ’‘Twitch
Twitch is a live streaming platform often used for gaming, but also for educational content. In the video, the instructor mentions offering free homework help on Twitch, indicating that students can join live streams to get help with their physics or math homework.
Highlights

Continuing with AP Physics one kinematics questions.

This is from the AP Physics B exam.

Discussing an experimental design problem.

Designing an experiment to determine acceleration due to gravity.

Using a small steel sphere and a recording plate.

The timer starts when the sphere is released.

The timer stops when the sphere strikes the recording plate.

Measuring the fall for different distances D.

Recording data in a table and plotting on a graph.

Sketching a smooth curve that best represents the data.

The data points suggest a quadratic relationship.

Using the kinematics equation to analyze the data.

Initial velocity is zero, hence the equation is one-half GT squared.

Plotting D versus 1/2 T squared for a linear relationship.

Computing values for 1/2 T squared for each data point.

Plotting the data points on a graph.

Estimating the slope of the line for acceleration G.

Discussing the accuracy of the experiment.

Suggesting increasing distances for better accuracy.

Offering free homework help on Twitch or Discord.

Transcripts
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