Energy and Momentum

With the current growth in interest in flywheels, stemming from concern for the environmental impact of fossil fuel use, flywheels provide a convenient way for storing energy.  Because of this, the study of flywheels in the physics curriculum is well worth consideration by teachers.  Such a study allows for a careful examination of the principles of conservation of energy, as well as both linear and rotational kinematics.  PocketLab Voyager’s ability to collect angular velocity data makes data collection much easier than was required in similar past experiments wit

A pendulum is held vertically and is  then released, impacting a cart that is initially at rest.  This experiment provides students with a lesson for comparing theory with actual experimental results and explaining any differences.  A variety of physics principles, including conservation of energy, conservation of momentum, and impulse, are incorporated into the experiment.  VelocityLab is used to determine the actual speed of the cart after the impact, and the students compare this to speed predictions based upon theory.  In addition, students use impulse concepts to calc

As shown in the image accompanying this lesson, conservation of angular momentum can be investigated using a Lazy Susan (LS), PocketLab, and a compact weight.   Voyager is mounted to the LS.  The LS is given a spin and gradually slows down from friction.   The compact weight is dropped just above the edge of the LS.  The resultant sudden decrease in angular velocity is recorded by Voyager.  The accompanying video shows all of this action.  Taking into account the moment of inertia of the LS, and

The PocketLab is an ideal device for measuring user performance for a variety of exercise equipment.  One example of such equipment is the Skier's Edge, whose company was founded in 1987.  This machine was designed for non-impact lateral conditioning that simulates the experience of downhill skiing.  The photo below shows the skiing machine.  The skier stands on the two black platforms, holding poles and moves the carriage back-and-forth on the curved white tracks.

Do you have two PocketLab Maker Kit carts, and do you have the free VelocityLab app?  Then you are all set to do some experiments in conservation of momentum with PocketLab!  This lab discusses how to setup and perform an inelastic collision in which one cart (A) is moving toward another cart (B) that is at rest.  When cart A hits cart B, they stick and move off together.  The photo below shows the two carts shortly before the collision would occur.  PocketLab is mounted on a front wheel of cart A.  Small pieces of wood are stuck to the carts and protrude further than the wheels.  Some thic

A well-known conservation of momentum experiment that has been around for many years involves dropping a brick onto a horizontally moving cart.  With PocketLab and the VelocityLab app, your students can perform this experiment easily with the cart from the PocketLab Maker Kit and a small block of wood.  The snapshot below shows the setup with the author about to drop the block of wood onto the cart coming from the left.  A pair of rails, with inside separation just a little larger than the axle of the carts, was constructed with thin balsa wood sticks.  This is optional but does help to kee

Do you have two carts from the PocketLab Maker Kits?  Do you have two PocketLabs?  You probably have at least two students in your physics class with iPhones.  Do they have the VelocityLap app installed on their iPhones?  Then you have the major components for your students to investigate conservation of momentum when two carts on a track "explode".

With gas prices as high as they are and having a growing concern for the environment, Americans today are becoming conscious about things they can do to improve fuel efficiency.  Many realize that driving at the posted speed limits promotes both safety and reduces the rate at which fuel is consumed.  With these things in mind, some have purchased hybrid vehicles including the Toyota Prius, all-electric vehicles such as the Nissan LEAF, or range-extending vehicles such as the Chevy Volt.  Those with EV's soon realize that they get more miles per charge if they avoid driving at excessively hi

An oscillating cart with a PocketLab provides an interesting way to study Newton's Second Law of Motion as well as some principles of damped harmonic motion.  The apparatus setup is shown in the figure below.  The small dynamics cart that can quickly be made from parts included in the PocketLab Maker Kit is shown in its equilibrium position.  Rubber bands are attached to each side of the cart and to two ring stands weighted down with some heavy books.  It is best to use rubber bands that provide as small Newton/meter as possible.  PocketLab is attached to the cart with its x-axis parallel t

PocketLab in conjunction with a 33-45-78 RPM turntable is an ideal setup for studying centripetal acceleration.  There are two videos that can be found in the Videos page of this web site.  They show that (1)  keeping radius constant implies that centripetal acceleration is proportional to the square of the velocity, (2) keeping velocity constant while varying the radius implies that centripetal acceleration is inversely proportional to the radius.