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Physics

Damped Simple Harmonic Motion

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Submitted by Rich on Sun, 07/07/2019 - 19:47

Introduction

Damping causes oscillatory systems to dissipate energy to their surroundings.  Frictional losses are quite common in mechanical systems and result in damped simple harmonic motion.  For example, when a child stops pumping a swing, the amplitude of the oscillations gradually decay toward zero.  The same thing happens to a mass that hangs from an oscillating spring.  It is quite common for the amplitude of such oscillations to exhibit a behavior that is negative exp

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The Negative Exponential Nature of Damping

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Submitted by Rich on Mon, 06/24/2019 - 20:50

Introduction

Damping causes oscillatory systems to dissipate energy to their surroundings.  Frictional losses are quite common in mechanical systems.  For example, when a child stops pumping a swing, the amplitude of the oscillations gradually decay toward zero.  The same thing happens to a mass that hangs from an oscillating spring.  It is quite common for the amplitude of such oscillations to exhibit a behavior that is negative exponential over time, as shown in Figure 1.  The graph indicates that if we take the amplitude at time t=0 to be 1, then the amplitude at time

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PocketLab University - Principles of Temperature Sensors

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Submitted by clifton on Thu, 06/20/2019 - 20:41

PocketLab University

PocketLab University is an initiative to develop college-level labs that students can conduct at home, in their dorm room, or in any other setting without the need for laboratory equipment. Lab 1 uses PocketLab Voyager to understand the physical principles that enable temperature sensors to convert the physical property of temperature to an electrical property that we can measure with simple circuitry. The student assignment is below.

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Resonance and Damped Harmonic Motion

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Submitted by Rich on Thu, 06/20/2019 - 02:47

Introduction

Resonance can be defined in a number of ways.  The most common definition is that resonance occurs at the frequency at which forced oscillations produce maximum amplitude.  When the driving forces of oscillation are removed, friction gradually decreases the amplitude.  This is known as damped harmonic motion.  Most young children experience resonance as well as damped harmonic motion in schoolyard playgrounds.  They experience resonance while pumping the swing at the right frequency--the natural frequency of the swing.  They experience dampe

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Periodic Motion: Weights vs. Springs

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Submitted by Rich on Thu, 06/13/2019 - 16:54

Introduction

In a well-known 1938 book entitled "Demonstration Experiments in Physics", editor Richard Sutton describes a setup for producing periodic motion of a cart using weights instead of springs.  With today's technology this experiment can be done using an air disk, and data can be collected with PocketLab Voyager's rangefinder.  The data clearly shows that not all periodic motions are simple harmonic.  The restoring force when weights are used is constant, while the restoring force with springs is proportional to the displacement.  Springs produce simple harmonic

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Momentum Pendulum Rides the PocketLab HotRod

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Submitted by Rich on Sun, 05/26/2019 - 23:36

The Momentum Pendulum

The momentum pendulum is shown in Figure 1.  A frame (red) to hold the pendulum was printed on a 3D printer.  The STL file in included with this lesson.  The frame is solidly attached to the PocketLab HotRod with three damage-free hanging strips.  A roughly 3" diameter  wood ball with a screw eye attached to the top of the ball is hung from a bifilar suspension so that the ball will swing in a plane.  Two small holes at the top of the frame provide an easy way to prepare the string suspension.  The smaller set of wheels are used with the HotRod, and

Physics Galore with the PocketLab Swing

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Submitted by Rich on Mon, 05/20/2019 - 16:00

The PocketLab Voyager Swing

The PocketLab Voyager swing, 3D printable from the accompanying .STL file, offers your physics students a way to study a plethora of physics concepts in a single experiment. Figure 1 shows a closeup up the swing, approximately inches tall, inches wide, and inches deep.

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Competing Pendulums

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Submitted by Rich on Sat, 05/18/2019 - 19:30

Competing Pendulums

The two pendulums shown in Figure 1 were printed on a 3D printer.  The .STL file is included with this lesson so you can print them with your 3D printer.  They have the same length, same mass, and same thickness.  They swing about a piece of metal rod from a coat hanger.  To provide a rigid support, the rod has been attached to a ring stand.  A tiny magnet has been taped to the bottom of each pendulum.  PocketLab Voyager's magnetic field sensor keeps track of the motion as the pendulums swing back-and-forth.  What is your prediction as to which one has

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Simple Harmonic Motion Demonstration Machine

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Submitted by Rich on Thu, 05/09/2019 - 14:52

Introduction

In a well-known 1938 book entitled "Demonstration Experiments in Physics", editor Richard Sutton describes a device that produces simple harmonic motion (SHM) mechanically.  With today's tremendous growth in the 3D printing industry, such a device can now be easily constructed for classroom demonstrations of SHM.  Couple this device with PocketLab Voyager and you can obtain real-time graphs describing the motion.

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