Recent years have seen an immense development in the field of X Reality (augmented, virtual, and mixed reality), empowering healthcare, education, and entertainment, and the trend predicts an exponential increase in the upcoming years. Augmented reality is a technology in which real-world environments can be enhanced by adding computer-generated…

This work is inspired by a recent article in a German newspaper about the question of whether a 360 degree turn on an ordinary swing, that is, a seat suspended by chains, is possible. Although the author correctly negates the question, his remarks about the trajectory of the rocking person remain imprecise. Thus, we direct our attention to cases…

In the teaching and learning of physics, simulations have many applications. Simulations can help to illuminate concepts (such as the motion of electrons in electric or magnetic fields) that cannot usually be seen with the unaided eye, or to slow down things that happen over short time periods or at high speeds. They can also be used to help…

In the physics teaching community, Tracker is well known as a user-friendly open source video analysis software, authored by Douglas Brown. With this tool, the user can trace markers indicated on a video or on stroboscopic photos and perform kinematic analyses. Tracker also includes a data modeling tool that allows one to fit some theoretical…

The trebuchet has quickly become a favorite project for physics and engineering teachers seeking to provide students with a simple, but spectacular, hands-on design project that can be applied to the study of projectile motion, rotational motion, and the law of conservation of energy. While there have been free trebuchet simulators and range…

On July 16, 1988, Florence Griffith Joyner (FGJ) shattered the women's 100-m dash world record (WR) with a time of 10.49 s, breaking the previous mark by an astonishing 0.27 s. By all accounts FGJ dominated the race that day, securing her place as the premiere female sprinter of that era, and possibly all time. In the aftermath of such an…

During the 17th century the idea of an orbiting and rotating Earth became increasingly popular, but opponents of this view continued to point out that the theory had observable consequences that had never, in fact, been observed. Why, for instance, had astronomers failed to detect the annual parallax of the stars that "must" occur if…

On Aug. 13, 2011, at 8:45 p.m. country music fans were eagerly awaiting the band Sugarland to make its entry onto the main stage at the Indiana State Fairgrounds. Also competing for the fans' attention was an approaching storm. Sugarland never made their entrance. At 8:49 p.m. the stage rigging was hit by 59 mile/h (94 km/h) winds causing it to…

The concept of "perpetual motion" has a long history. The Indian astronomer and mathematician Bhaskara II (12th century) was the first person to describe a perpetual motion (PM) machine. An example of a 13th-century PM machine is shown in Fig. 1. Although the law of conservation of energy clearly implies the impossibility of PM construction, over…

In 1879, in the midst of the debate between English and continental scientists about the nature of cathode rays, William Crookes conducted an experiment in which a small mill or "paddle wheel" was pushed along tracks inside a cathode ray tube (CRT) (similar to that shown in Fig. 1) when connected to a high-voltage induction coil. Crookes…

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)

Offers a relatively simple analysis of the asymmetrical "sticking" and rolling behavior of two balls, one steel and one rubber, on an incline. Describes an Interactive Physics (TM) simulation designed to study the problem and gives rough experimental results. (WRM)

Discusses how a spreadsheet might be used in an introductory physics laboratory. Describes three categories of spreadsheet uses, advantages of spreadsheet, layout, accuracy, and modifications. Gives an example of the variable mass rocket problem with typical display. (YP)

Presents five models of the human body as a mechanical system which can be used in introductory physics courses: human arms as levers, humans falling from small heights, a model of the human back, collisions during football, and the rotating gymnast. Gives ideas for discussions and activities, including Interactive Physics (TM) simulations. (WRM)

Introduces a computer solution of the oscillation of a mass suspended by a spring in a viscous liquid. Describes the equations of motion, spreadsheet solution, copying the formulas, plotting the results, and extending the applications. Presents spreadsheet and physics formulas for the step-by-step solution and spreadsheet solution. (YP)