2016 AP Physics 1 Free Response #2

Allen Tsao The STEM Coach
18 Sept 201805:54
EducationalLearning
32 Likes 10 Comments

TLDRIn this educational video, Alan from Bothell STEM discusses a hypothetical experiment to test the elasticity of ball collisions. He suggests using a high-speed camera and a meter stick to measure the bounce height and compares it to the drop height to determine energy conservation. The data should ideally show a linear relationship, with deviations indicating non-elastic collisions. Alan also addresses possible experimental errors and offers free homework help on Twitch and Discord for further learning.

Takeaways
  • πŸš€ Alan from Bothell STEM is coaching AP Physics students on free response questions.
  • πŸ” The discussion focuses on testing the hypothesis of perfectly elastic collisions using a new kind of toy ball.
  • πŸ€” A student suspects that no collision can be perfectly elastic, especially at higher speeds.
  • 🧐 The student proposes that collisions might be close to perfectly elastic at low speeds but deviate at higher speeds.
  • πŸ“ The experiment involves bouncing the ball from various heights to measure drop and bounce heights.
  • πŸ“ Equipment suggested includes a high-speed camera, a meter stick, and a measurement tape.
  • πŸ“‰ The data will be represented graphically to compare potential energy before and after the collision.
  • πŸ“ˆ A perfectly elastic collision would show equal potential energy before and after the bounce on the graph.
  • πŸ“Š Any deviation from a straight line on the graph would indicate a loss of energy during the collision.
  • πŸ” The student's experiment aims to analyze whether the collisions are consistent with the hypothesis of elasticity.
  • πŸ€” A graph or table showing more energy after the collision than before would violate the conservation of energy principle.
  • πŸ“š Alan offers free homework help on Twitch or Discord for students with questions in math and physics.
Q & A
  • What is the main topic of the video script?

    -The main topic of the video script is designing an experiment to test the hypothesis about the elasticity of collisions of a ball with a hard surface.

  • What is the student's hypothesis regarding the ball's collisions?

    -The student's hypothesis is that collisions are very close to being perfectly elastic at low speeds but deviate more from perfect elasticity as the collision speed increases.

  • What type of equipment would be used in the experiment according to the script?

    -The equipment mentioned includes a high-speed camera, a meter stick or measurement tape, and possibly a school Physics Laboratory setup.

  • How would the student measure the height of the ball's bounce?

    -The student would use a high-speed camera to record the ball's motion and a measurement tape to measure the drop height and bounce height.

  • What quantities would be measured in the experiment?

    -The quantities measured would include the potential energy before and after the collision, which is represented by the product of mass (M), gravity (G), and height (H).

  • How would the data be represented in the experiment?

    -The data would be represented in a graph or table, comparing the potential energy before and after the collision.

  • What would a perfectly elastic collision look like on the graph?

    -A perfectly elastic collision would be represented by a straight line where the potential energy before and after the collision is equal (y = x).

  • What would the graph show if the experiment violated the conservation of energy?

    -If the conservation of energy is violated, the graph would show that the potential energy after the collision is more than before the collision, indicating an increase in energy.

  • What does the student conclude if the graph or table shows non-elastic behavior for low-speed collisions?

    -The student would conclude that something went wrong with the experiment because non-elastic behavior at low speeds would violate a basic physics principle.

  • How would the student test the hypothesis comparing low versus high-speed results?

    -The student would test the hypothesis by comparing the ratio of potential energy after collision to before collision as a function of pre-collision speeds, expecting it to stay near one for low speeds and deviate for high speeds.

  • What additional service does Alan offer for students who have homework questions?

    -Alan offers free homework help on Twitch or Discord for students who have questions about math and physics or just want to learn and hang out.

Outlines
00:00
πŸ”¬ Designing an Experiment to Test Elastic Collisions

In this paragraph, Alan from Bothell STEM coach introduces a hypothetical scenario where a student is skeptical about the perfect elasticity of a new kind of toy ball. The student suggests that low-speed collisions might be close to perfectly elastic, but as the speed increases, the collisions deviate from this ideal. Alan proposes an experiment to test this hypothesis using common school Physics Laboratory equipment. The plan involves bouncing the ball from varying heights to measure the drop and bounce heights, using a high-speed camera and a measuring tape. The data will be represented in a graph or table to compare the potential energy before and after the collision, which will help determine if the collisions are perfectly elastic. A deviation from a straight line in the graph would indicate energy loss during the collision, thus disproving the hypothesis of perfect elasticity.

05:02
πŸ“Š Analyzing Experimental Data for Energy Conservation

Alan continues the discussion by addressing how the student should analyze the experimental data. The student is expected to plot a graph comparing the mechanical energy before and after the collision with a hard surface. If the graph shows that the energy after the collision is more than before, it would violate the principle of conservation of energy, indicating an error in the experiment. Alan suggests that a correct graph would show the ratio of post-collision to pre-collision energy near one for low-speed collisions, and then deviate as the speed increases, demonstrating the loss of elasticity at higher speeds. He also mentions offering free homework help on Twitch or Discord for those interested in further learning about math and physics.

Mindmap
Keywords
πŸ’‘Elastic Collision
An elastic collision is a type of collision where both momentum and kinetic energy are conserved. In the video, the concept is central to the experiment's hypothesis, which is to test whether a ball can bounce perfectly elastically off a hard surface. The student suspects that the collisions are nearly elastic at low speeds but deviate from perfect elasticity at higher speeds.
πŸ’‘Potential Energy
Potential energy is the stored energy of an object due to its position in a force field, such as gravity. In the context of the video, potential energy (MGH) is used to measure the energy of the ball before and after the collision to determine if the collision is elastic. The script mentions comparing the potential energy before the drop to after the bounce to see if it remains constant, indicating an elastic collision.
πŸ’‘Speed
Speed refers to the rate at which an object moves. The video discusses varying the speed of the ball by changing the height from which it is dropped, which affects the energy and elasticity of the collision. The hypothesis is that collisions are more elastic at lower speeds and less so as speed increases.
πŸ’‘High-Speed Camera
A high-speed camera is a device capable of capturing images at a much higher frame rate than the normal eye can see. In the script, it is suggested to use a high-speed camera to record the ball's motion during the bounce, allowing for precise measurement of the bounce height and the analysis of the collision dynamics.
πŸ’‘Meter Stick
A meter stick is a measuring tool used to determine the length or height of an object. In the video script, a meter stick or a measuring tape is proposed to measure the drop height and the bounce height of the ball, which are essential for calculating potential energy and analyzing the collision.
πŸ’‘Energy Conservation
Energy conservation is a fundamental principle stating that the total energy of an isolated system remains constant over time. The video's experiment is designed to test this principle by comparing the energy before and after the collision. If the energy after the collision is more than before, it would violate the principle, indicating a non-elastic collision.
πŸ’‘Graph
A graph is a visual representation of data, typically used to show relationships between variables. In the script, the student plans to represent the data in a graph to determine if the collisions are elastic. The graph would compare the potential energy before and after the collision, with a straight line indicating perfect elasticity.
πŸ’‘Experiment
An experiment is a scientific procedure undertaken to make a discovery, test a hypothesis, or demonstrate a known fact. The video describes an experiment to test the hypothesis about the elasticity of collisions. The experiment involves bouncing a ball from various heights and measuring the bounce height to analyze energy loss.
πŸ’‘Hypothesis
A hypothesis is a proposed explanation for a phenomenon, made as a starting point for further investigation. In the video, the student's hypothesis is that collisions are nearly perfectly elastic at low speeds but become less so as the speed of the collision increases, which the experiment aims to test.
πŸ’‘Physics Laboratory
A physics laboratory is a place where scientific experiments related to physics are conducted. The script mentions that the student has access to equipment typically found in a school physics laboratory, such as a high-speed camera and a meter stick, to carry out the experiment.
πŸ’‘Free Response Question
A free response question is an open-ended question that requires a detailed answer, often used in assessments to gauge a student's understanding and ability to apply knowledge. The video is a discussion of a free response question from the AP Physics exam, focusing on designing an experiment to test a hypothesis about collisions.
Highlights

Alan introduces the continuation of the AP Physics 2016 free response questions.

Discussion of a new toy ball advertised to bounce perfectly elastically off hard surfaces.

A student's hypothesis that no collision can be perfectly elastic is presented.

The student's observation that collisions are close to perfectly elastic at low speeds but deviate at higher speeds.

Designing an experiment to test the hypothesis about the ball's collisions.

Equipment available in a school Physics Laboratory is mentioned for conducting the experiment.

Suggestion to measure the ball's drop height and bounce height to determine energy loss during collisions.

Use of a high-speed camera and a meter stick for precise measurement of the ball's motion.

Explanation of how the data will be represented in a graph or table to analyze energy conservation.

Comparison of potential energy before and after the collision to test for perfect elasticity.

Description of how a deviation from a straight line in the graph would indicate non-perfect elasticity.

The student's immediate conclusion that something went wrong with the experiment due to unexpected results.

Explanation of how the graph or table should show elastic behavior for low-speed collisions.

Discussion of a basic physics principle that seems to be violated in high-speed collisions.

Proposal of a conceptually plausible plan to measure the ball's collision positions.

Suggestion to use a meter stick to measure heights and record the ball's motion against a wall.

Application of data analysis to test the hypothesis by comparing low versus high-speed results.

Proposal to graph the ratio of energy conservation as a function of pre-collision speeds.

Alan's offer of free homework help on Twitch or Discord for those interested in math and physics.

Transcripts
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