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Monkey and Hunter Projectile JavaScript HTML5 Applet Simulation Model

 

 

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About

About

Topics

Kinematics
Non-linear motion

Description

Play with the 2 Cannon pointing at each model. This simulation can be used to illustrate the thought experiment "The Monkey and the Hunter" often used to illustrate the effect of gravity on projectile motion.

The Monkey and the Hunter Experiment

A hunter with a blowgun goes out in the woods to hunt for monkeys and sees one hanging in a tree, at the same level as the hunter's head. The monkey, we suppose, releases its grip the instant the hunter fires his blowgun. Where should the hunter aim and when should he fire in order to hit the monkey?

Question: 

Do you know why the cannonball always hit each other provided they point at each other and velocities are pointed towards each other and greater than zero?

Answer :

is conceptually in the green line being without the effects of gravity, the cannons ball will meet as predicted by Newton's 1st Law of motion without net external force.
now, adding the same gravitational acceleration means both cannon balls will move down at the same rate ( pink lines).
therefore, the 2 cannon balls has to collide .

Sample Learning Goals

(g) solve problems using equations which represent uniformly accelerated motion in a straight line, including the motion of bodies falling in a uniform gravitational field without air resistance

Version:

  1. http://weelookang.blogspot.sg/2015/02/ejss-2-cannon-aim-at-each-other.html
  2. http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=144.0

Project related:

Understanding Teacher Learning Community as Support for Implementation of Open Source Physics for Conceptual Instruction
Project Number: OER 10/15 GWF
Project Duration: 01 July 2015 - 30 April 2017

http://weelookang.blogspot.sg/2015/07/understanding-teacher-learning.html

 

Translations

Code Language Translator Run

Credits

This email address is being protected from spambots. You need JavaScript enabled to view it.; Fu-Kwun Hwang

https://sg.iwant2study.org/ospsg/index.php/interactive-resources/physics/02-newtonian-mechanics/01-kinematics/40-projectile2cannon

Monkey and Hunter Projectile Motion Study Guide

Quiz

Instructions: Answer the following questions in 2-3 sentences each.

  1. What is the central concept illustrated by the Monkey and Hunter thought experiment?
  2. Where should the hunter aim to hit the monkey that drops the instant the hunter fires?
  3. Why does the simulation use cannons instead of a hunter and a blowgun?
  4. How does Newton's First Law of Motion relate to the Monkey and Hunter scenario?
  5. What is the significance of the green line in the simulation's visual representation?
  6. What do the pink lines in the simulation's visual representation demonstrate?
  7. Would the outcome be different if the monkey took a moment to react before dropping? Explain.
  8. What real-world factors are ignored in the simplified model of this experiment?
  9. How does understanding projectile motion apply to fields beyond physics?
  10. If the cannonballs were launched at different speeds, would they still collide? Explain.

Quiz Answer Key

  1. The Monkey and Hunter experiment demonstrates that gravity affects both the projectile (the dart or cannonball) and the falling object (the monkey) equally, leading to their collision regardless of the monkey's release timing.
  2. The hunter should aim directly at the monkey. Even though the monkey falls, the projectile and the monkey fall at the same rate due to gravity.
  3. Cannons are used to provide a more controlled and dramatic visualization of the concept. They allow for precise adjustments of velocity and trajectory, simplifying the demonstration.
  4. Newton's First Law states that an object in motion stays in motion at a constant velocity unless acted upon by a net force. In the idealized scenario, without gravity, the cannonballs would follow a straight path (green line) and collide due to their initial velocities.
  5. The green line represents the trajectory of the cannonballs if gravity was not a factor. This line helps visualize the concept that the cannonballs would collide even without gravity.
  6. The pink lines represent the actual trajectories of the cannonballs under the influence of gravity. They illustrate that both cannonballs experience the same vertical acceleration, causing them to fall at the same rate.
  7. Yes, if the monkey delayed its drop, the cannonball would likely miss. The precise timing of simultaneous release is crucial for the collision to occur.
  8. The simulation ignores factors like air resistance, variations in gravitational pull, and the size of the objects involved, all of which could influence the outcome in a real-world setting.
  9. Understanding projectile motion is essential in fields like sports (throwing a ball), engineering (designing bridges), and military applications (calculating missile trajectories).
  10. If launched at different speeds, the cannonballs would likely miss. The collision relies on their identical vertical acceleration due to gravity, which dictates their falling rate.

Essay Questions

  1. Discuss the role of idealization and simplification in scientific models, using the Monkey and Hunter experiment as an example.
  2. Explain in detail how the concepts of horizontal and vertical motion are independent of each other in projectile motion.
  3. Analyze the ethical implications of the Monkey and Hunter thought experiment. Should such models be used for educational purposes?
  4. Research and describe real-world applications of projectile motion principles in fields other than physics.
  5. Design an alternative experiment to demonstrate the same concept as the Monkey and Hunter, explaining the rationale behind your choices.

Glossary

TermDefinitionProjectile motionThe curved path an object follows when thrown or launched near the Earth's surface. It is influenced by gravity and the object's initial velocity.GravityThe force of attraction between any two objects with mass. On Earth, it causes objects to fall towards the center of the planet.Newton's First LawAlso known as the Law of Inertia. It states that an object at rest stays at rest, and an object in motion stays in motion at a constant velocity unless acted upon by a net force.TrajectoryThe path an object follows as it moves through space.Horizontal motionMovement along the x-axis, parallel to the ground. In projectile motion, it is typically constant and unaffected by gravity.Vertical motionMovement along the y-axis, perpendicular to the ground. In projectile motion, it is influenced by gravity and results in the object's upward or downward movement.AccelerationThe rate of change of velocity over time. It can be positive (speeding up), negative (slowing down), or zero (constant velocity).Air resistanceA force that opposes the motion of an object through the air. It is influenced by the object's shape, size, and speed.Thought experimentA hypothetical scenario used to explore and analyze complex ideas or concepts. It doesn't involve physical experimentation but relies on logic and reasoning.Scientific modelA simplified representation of a real-world system or phenomenon. It helps understand, explain, and predict behavior but often involves idealizations and assumptions to make the model manageable.Uniformly accelerated motionMotion where the object's velocity changes at a constant rate. This means its acceleration is constant. For example, an object in free fall experiences uniformly accelerated motion due to the constant gravitational acceleration.

Briefing Doc: Monkey and Hunter Projectile Simulation

Source: "Monkey and Hunter Projectile JavaScript HTML5 Applet Simulation Model" from Open Educational Resources / Open Source Physics @ Singapore

Theme: This resource focuses on illustrating the classic "Monkey and Hunter" physics problem, which demonstrates the effects of gravity on projectile motion. It utilizes an interactive simulation to visually explain the concept.

Key Ideas & Facts:

  • The Monkey and Hunter Experiment: A hunter aims directly at a monkey hanging from a tree. The monkey releases its grip at the exact moment the hunter fires. The question posed is: where should the hunter aim to hit the monkey, considering gravity's influence?
  • Simulation Model: The provided HTML5 applet simulates this scenario with two cannons aimed at each other. Users can manipulate variables to observe the projectile paths and understand the underlying physics.
  • Explanation of the Phenomenon: The simulation helps visualize that even though gravity pulls both projectiles downwards, they fall at the same rate. This ensures a collision, as explained in the source: “adding the same gravitational acceleration means both cannon balls will move down at the same rate (pink lines). Therefore, the 2 cannon balls have to collide."
  • Educational Application: The resource is intended for secondary and junior college level students learning about kinematics, dynamics, and non-linear motion. It provides:
  • Interactive learning through the simulation
  • Worksheets for practice
  • Sample learning goals aligned with curriculum standards
  • Links to videos demonstrating the experiment in real life

Important Quotes:

  • "This simulation can be used to illustrate the thought experiment 'The Monkey and the Hunter' often used to illustrate the effect of gravity on projectile motion."
  • "Do you know why the cannonball always hit each other provided they point at each other and velocities are pointed towards each other and greater than zero?"
  • "is conceptually in the green line being without the effects of gravity, the cannons ball will meet as predicted by Newton's 1st Law of motion without net external force."

Overall: This Open Educational Resource provides an engaging and interactive tool for teaching and learning about projectile motion and the "Monkey and Hunter" problem. It effectively uses visualization and experimentation to solidify understanding of key physics concepts.

Apps

Quick Survey for HCI Lessons for 3 simulations

https://goo.gl/forms/nCJpO5rz9uHiT2aJ2

Results

https://docs.google.com/forms/d/1Odtqyh_Qt22VsMGt4v0Kv5Po7OusxyC-x6wzQMJBZa8/viewanalytics

Topics

Kinematics
Non-linear motion

Description

Play with the 2 Cannon pointing at each model. This simulation can be used to illustrate the thought experiment "The Monkey and the Hunter" often used to illustrate the effect of gravity on projectile motion.

The Monkey and the Hunter Experiment

A hunter with a blowgun goes out in the woods to hunt for monkeys and sees one hanging in a tree, at the same level as the hunter's head. The monkey, we suppose, releases its grip the instant the hunter fires his blowgun. Where should the hunter aim and when should he fire in order to hit the monkey?

Question: 

Do you know why the cannonball always hit each other provided they point at each other and velocities are pointed towards each other and greater than zero?

Answer :

is conceptually in the green line being without the effects of gravity, the cannons ball will meet as predicted by Newton's 1st Law of motion without net external force.
now, adding the same gravitational acceleration means both cannon balls will move down at the same rate ( pink lines).
therefore, the 2 cannon balls has to collide .

Worksheet

  1. ejss_model_kinematics CT_kinematics (1017).ppt 
  2. ejss_model_kinematics Motion in One Dimension student worksheet (2017).docx
  3. Motion in One Dimension student worksheet (dl-gwf) Link1, Link2  by Lyna, Gavin, Dave and lookang 

Sample Learning Goals

(g) solve problems using equations which represent uniformly accelerated motion in a straight line, including the motion of bodies falling in a uniform gravitational field without air resistance

Video

  1. https://youtu.be/cxvsHNRXLjw  MIT Physics Demo -- Monkey and a Gun by mittechtv 
  2.  Monkey and Hunter Apparatus Demonstration by The Amazing Cenco Physics Presents
  3. https://www.stem.org.uk/elibrary/resource/27021/monkey-and-hunter Demo by Alom Shaha from National STEM Centre
  4. https://www.physics.umn.edu/video.html?url=/media/outreach/pforce/circus/videos/MechanicsProjectileMotion-MonkeyAndHunter.flv&vidname=Physics%20Force:%20Monkey%20and%20Hunter&goback=/outreach/pforce/circus/ by University of Minnesota
  5. https://notebooklm.google.com/notebook/1ad320d9-33a3-4525-a636-b3be227e9300/audio

Version:

  1. http://weelookang.blogspot.sg/2015/02/ejss-2-cannon-aim-at-each-other.htmlcustomization by Loo Kang Wee
  2. http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=144.0 original by Fu-Kwun Kwang
  3. http://www.opensourcephysics.org/items/detail.cfm?ID=10114&S=7 another copy by Fu-Kwun Kwang in OSP

Other Simulations

  1. http://www.physicsclassroom.com/Physics-Interactives/Vectors-and-Projectiles/The-Monkey-and-the-Zookeeper/The-Monkey-and-the-Zookeeper-Interactive by The Physics Classroom
  2. https://tube.geogebra.org/material/show/id/53219 Projectile Motion: Tranquilize the Monkey GeoGeBra by ukukuku
  3. http://www.waowen.screaming.net/revision/force&motion/mandh.htm Flash simulation
  4. http://www.mhhe.com/physsci/physical/giambattista/proj/projectile.html Java simulation

Project related:

    2. Understanding Teacher Learning Community as Support for Implementation of Open Source Physics for Conceptual Instruction Project Number: OER 10/15 GWF Project Duration: 01 July 2015 - 30 April 2017 http://weelookang.blogspot.sg/2015/07/understanding-teacher-learning.html

Monkey and Hunter Experiment FAQ

1. What is the Monkey and Hunter experiment?

The Monkey and Hunter experiment is a classic physics thought experiment that demonstrates the effect of gravity on projectile motion. The scenario involves a hunter aiming a blowgun at a monkey hanging from a tree. The monkey releases its grip at the exact moment the hunter fires. The question is: where should the hunter aim to hit the falling monkey?

2. Where should the hunter aim to hit the monkey?

The hunter should aim directly at the monkey, even though it will be falling. This might seem counterintuitive, but gravity affects both the monkey and the projectile equally.

3. Why does aiming directly at the monkey work?

Imagine the projectile's path without gravity. It would travel in a straight line and hit the monkey, assuming the aim was correct. Now, add gravity. Both the monkey and the projectile fall at the same rate due to gravity. This means that the projectile's downward motion matches the monkey's fall, resulting in a collision.

4. What scientific principles does this experiment illustrate?

The Monkey and Hunter experiment illustrates:

  • Projectile Motion: Objects launched at an angle follow a curved path due to the influence of gravity.
  • Uniform Acceleration: Gravity causes all objects to accelerate downwards at the same rate, regardless of their mass.
  • Newton's First Law of Motion: An object in motion will stay in motion with the same speed and in the same direction unless acted upon by an external force. In this case, gravity acts as the external force.

5. Are there any real-world applications of this concept?

Yes, understanding projectile motion is crucial in various fields, including:

  • Military and Defense: Accurately predicting the trajectory of projectiles is essential for artillery and missile systems.
  • Sports: Athletes in sports like basketball, baseball, and golf must consider the projectile motion of the ball to achieve their desired outcome.
  • Space Exploration: Launching rockets and satellites requires precise calculations of projectile motion to ensure they reach their intended destinations.

6. Can I simulate the Monkey and Hunter experiment?

Yes, there are several online simulations and physical demonstrations of the Monkey and Hunter experiment. The source provided describes a JavaScript HTML5 applet simulation that allows you to manipulate variables like the projectile's velocity and observe the outcome.

7. What are some variations of this experiment?

The experiment can be varied by changing the initial height of the monkey, the velocity of the projectile, or introducing other factors like air resistance. More complex simulations can explore these variations.

8. Where can I find more resources about the Monkey and Hunter experiment?

Numerous resources, including videos, articles, and interactive simulations, are available online. Websites like The Physics Classroom and educational institutions like MIT have published materials explaining and demonstrating this classic experiment.