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

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

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

Introduction

"The brakes on my car have failed and I can fix either the front or rear brakes.  Which set of brakes should I fix if I am concerned with stability against spinning while braking?"   This quote is from an article by W. G.

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 5½ inches tall, 1¾ inches wide, and 1¾ inches deep.

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

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.

The PocketLab Inertia Cart

This cool inertia cart dates back to the early 1900's, but hasn't seen much action since, primarily due to a lack of ease in construction.  However, now with the PocketLab HotRod and three 3D printable parts whose .STL files are included with this lesson, you can use this demonstration in your classroom.  Depending upon the grade level of your students, you can customize the discussion as appropriate.  Concepts involved include Newton's Laws of Motion, pulleys, force, acceleration, Half-Atwood machine, inertia, and moment of inertia.

Engineering Crash Cushions to Learn Newton's Third Law

Newton's third law states that for every action, there is an equal and opposite reaction. By crashing a physics cart into a wall, various crash cushions can be used to reduce the forces experience by the cart.

Introduction to Moment of Inertia

There are numerous analogies when comparing linear and rotational motion.  At the heart of these comparisons lie the concepts of mass on one hand and moment of inertia on the other.  In addition to being a property of any physical object, mass is a measure of the resistance of an object to acceleration when a net force has been applied to the object.  Newton's Second Law of Motion expresses this in the fa