Lesson 4. Impulse: Dribbling a Basketball

Stephen Dickman, Jacob Kelter
Physics
Estimated time for students: two 45 minute periods.
AP Physics 1
v3

Overview

This simulation involves the modeling of a basketball hitting the ground and bouncing back up: it is a force, plus, impulse effect. All the physical quantities involved are graphically displayed in this model. Thus, the model reinforces the understanding of Newton's Laws.

Standards

Computational Thinking in STEM 2.0
  • Computational Modeling and Simulation Practices
    • [CT-MODEL-1] Using computational models to understand a complex phenomenon
    • [CT-MODEL-2] Using computational models to hypothesize and test predictions
    • [CT-MODEL-3] Using a computational tool to understand a system's compenents and dynamics
Next Generation Science Standards
  • Physical Science
    • [HS-PS2-1] Analyze data to support the claim that Newton’s second law of motion describes the mathematical relationship among the net force on a macroscopic object, its mass, and its acceleration.
    • [MS-PS4-2] Develop and use a model to describe that waves are reflected, absorbed, or transmitted through various materials.

Credits

This simulation and lesson would created by Stephen Dickman, Kelvin Lao and Jacob Kelter.

7/27/2020

Activities

  • 1. Introduction to dribbling a basketball
  • 2. Model of Falling Ball striking Floor.
  • 3. Reflection Questions

Student Directions and Resources


Learning Objectives

  • The student will view and better conceptualize all of Newton's Laws and the conservation of mechanical energy.
  • The student will learn that the change in momentum comes from Impulse, or net force acting times time(F x t).
  • The student will better conceptualize how a mass loses potential energy during a bounce.
  • The student will review motion and force graphs vs. time.

1. Introduction to dribbling a basketball


On this page you will explore the simulation below which contains a single ball falling and bouncing off the ground. 

Note: You will have to increase the speed slider to get it run at a good speed, but, if you want to explore the behavior at a certain moment, you can slow it back down. 


Question 1.1

Where is the acceleration not -9.8 m/s^2? Why? What is the name of the non-gravitational force acting during contact with the floor? What is the nature of this force, i.e., gravitational or electrical?



Question 1.2

Manipulate the value of the mass. During the initial fall, what is the different factor between the acceleration and the force graph? (Hint: there's just one quantity difference)



Question 1.3

How many different slopes are there on the velocity graph? Which one is the greatest slope? Why do you think this is so?



Question 1.4

How does each slope on the velocity graph relate to the acceleration graph?



Question 1.5

From which two graphs can you calculate the impulse? 



Question 1.6

During which two parts of the trip (in the air or contact with the ground) is the greatest change in momentum?



Question 1.7

What quantities will change as you vary the mass? What quantities don't?



Question 1.8

During what part of the trip is the gravitational potential + kinetic energy constant? Where is it not constant? What do we call this part of the trip?



Question 1.9

You'll notice a downward spike in the (kinetic + gravitational) energy when the ball is stopped on the floor. Where do you think the energy is? 



Question 1.10

Draw the shape that a real ball would have (1) when it is falling and (2) when its gravitational + kinetic energy is zero. 

Note: Draw your sketch in the sketchpad below


Question 1.11

Why is the Kinetic Energy vs. time graph quadratic?



Question 1.12

List which physical quantities change when you change the mass of the ball.



Question 1.13

Sketch the force vs. time graph during the whole trip. What does the area under/over force value represent?

Note: Draw your sketch in the sketchpad below


Question 1.14

Sketch the forces on the ball during free fall, neglect air resistance. Sketch the forces on the ball during the contact with the floor. Draw according to appropriate magnitude.

Note: Draw your sketch in the sketchpad below


Question 1.15

Sketch a graph of the ball's momentum vs. time. Which displayed graph is this very nearly like?



Question 1.16

General Review: Describe each of Newton's Laws in play as the ball falls. As the ball strikes the floor.

2. Model of Falling Ball striking Floor.


The students must press set up and go to run the simulation. 

Note: You can make the model run faster by sliding the model speed icon to the right.

In this simulation, we are modeling a basketball with 7 "atoms" connected by springs. So each turtle (circle) in the simulation feels the force of gravity, the force of the springs it is connected to, and the force of hitting the ground. 


Question 2.1

What is the state of motion of the upper two middle turtles when the lowest one first makes contact with the floor? Why is this so? Which law(s) of Newton is in play here?



Question 2.2

What exactly does the area under the force vs time graph equal?



Question 2.3

Why does the ball not achieve it original height after one bounce? How does the simulation demonstrate this?



Question 2.4

Is the ball always undergoing a change in momentum during this simulation? Why do you know this?



Question 2.5

What is the value of the ball's momentum at some point during the initial fall? If the mass were doubled, what would it be?



Question 2.6

Draw the force vectors on the ball as it is falling and during contact with the ground.

Note: Draw your sketch in the sketchpad below


Question 2.7

What, exactly, represents heat in this model. Do you think that heat could lift up the ball to its original height again?



Question 2.8

Force Considerations

Change the strength of the impact force(How do you do this?) and see what happens?

Change the strength of the spring force holding these turtles together, what happens? How do you do this?



Question 2.9

What do you think elasticity represents in this model or in the whole physical world?



Question 2.10

What line would you have to edit to make this model appropriate for a falling ball on the Moon? If the acceleration due to gravity on the Moon is 1/6 the value on Earth, what value would you change in this code line?

3. Reflection Questions


This page asks you to answer some reflection questions related to all the CT-STEM lessons you have done so far. 

 

 


Question 3.1

Write at least one big idea that you learned about physics in this lesson or in earlier CT-STEM lessons.



Question 3.2

Pick any computational tool/activity that you have used in this lesson or in earlier CT-STEM lessons. Briefly describe the tool and explain how you used it to learn. 



Question 3.3

Indicate how much you agree or disagree with the following statements:

I enjoyed learning with computational tools/activities so far in this unit.

  Strongly disagree
  Disagree
  In the middle/ I don't know
  Agree
  Strongly agree


Question 3.4

Indicate how much you agree or disagree with the following statement:

I feel that I successfully learned the content of this lesson.

  Strongly disagree
  Disagree
  In the middle / I don't know
  Agree
  Strongly agree


Question 3.5

Compared to lessons without computational tools/activities, I found this lesson more engaging.

  Strongly disagree
  Disagree
  In the middle/ I don't know
  Agree
  Strongly agree


Question 3.6

Indicate how much you agree or disagree with the following statement:

Compared to lessons without computational tools/activities, I found this lesson more challenging.

  Strongly disagree
  Disagree
  In the middle / I don't know
  Agree
  Strongly agree


Question 3.7

Indicate how much you agree or disagree with the following statement:

I felt stressed by the computational tools/activities we have done in this lesson.

  Strongly disagree
  Disagree
  In the middle / I don't know
  Agree
  Strongly agree


Question 3.8

Is anything that you learned in this unit relevant to your personal aspirations? If yes, please explain.