Researchers and practitioners alike express concerns about the conceptual difficulties associated with the concepts of momentum and kinetic energy currently taught in school physics. This article presents an in-depth analysis of the treatment given to them in 44 published textbooks written for UK secondary school certificate courses. This is set…

Discusses the theory behind a study of motion where a hollow plastic sphere racing against a steel sphere in two parallel sections of inclined channeling always reaches the bottom first; once on the floor, however, the steel sphere travels faster, speeding past the plastic sphere when both are about one meter from the base of the track. (JRH)

Describes a simple setup and procedure that uses "happy/unhappy" balls (two balls with different degrees of elasticity) to lead students into a discussion of momentum transfer involving elastic and inelastic collisions. (ZWH)

Provides an analysis of the forces causing the erratic motion of a knuckleball. Reveals the manner the ball should be thrown to provide maximum deflection. (Author/CP)

The circular motion observed when water drains into a smooth opening is analyzed. This action, as well as cycloidal atmospheric motion, is explained as the result of rotation of the coordinate system. (CP)

Describes the design and use of a projectile motion apparatus to illustrate a variety of projective motion results typically discussed in an introductory course. They include independence of horizontal (constant speed) and vertical (constant acceleration) motions, parabolic path shape, and other types of motion. (JN)

Describes experiments involving variations on the electroscope, an electrostatic toy, a stationary wave machine, a spark counter, a carbon microphone, curvilinear expansion, soap films, a barber's pole, and a simple pendulum. (GS)

Provides information on the calculation of the redshift to blueshift ratio introduced by the transverse Doppler effect at relativistic speeds. Indicates that this shift should be mentioned in discussions of whether quasars are "local" rather than "cosmological" objects. (GS)

Discussed are details of what is known about the composition, physical characteristics, and formation of the planet Pluto and its satellite, Charon. Alignments of these bodies and details of their rotations and revolutions are described. (CW)

Describes four kinds of movement by a cat with or without angular momentum and tail or tail-less during free falling. Presents many pictures illustrating the movement. Supports the position that the angular momentum of the tail plays an important role in free fall. (YP)

Presents the theory behind the mechanics demonstration that involves projecting a ball vertically upward from a ballistic cart moving along an inclined plane. The measured overshoot is believed to be due, in part, to the presence of rolling friction and the inertial properties of the cart wheels. (JRH)

Presents activities to teach the concept of projectile motion to high school students using a spring-loaded dart gun, carbon paper, meterstick, ruler, white paper, tape, and a student's desk. (JRH)

A phenomena, boundary layer control (BLC), produced when visualizing the fluidlike flow of air is described. The use of BLC in modifying aerodynamic characteristics of airfoils, race cars, and boats is discussed. (KR)

A professor of physics discusses ideas on how to use physics to improve your ping-pong game. Describes how basic physics was used to analyze a simple ball-paddle collision problem and provide students with insight on the application of physics to a fun and real life situation. (ZWH)