Calculating the duration of a motion when the applied net force on the moving body changes with time is usually a challenging task. In most cases, the only example of the duration of a motion when the acceleration is not constant presented to introductory physics students worldwide is the example of harmonic motion. A discussion with respect to…

Most springs do not simply obey Hooke's law because they are constructed to have an initial tension, which must be overcome before normal elongation occurs. This property, well known to engineers, is universally neglected in elementary physics courses. In particular, the standard simple harmonic motion experiment omits any discussion of this…

The conservation law of energy and momentum can be examined and demonstrated by a well-known collision experiment. In this experiment, several identical elastic balls are suspended from a horizontal frame. When the ball at one end is pulled aside and released, thus allowing it to swing like a pendulum, it hits the next ball. The outcome is…

In an article in this journal, it was shown that air resistance could never be a significant source of error in typical free-fall experiments in introductory physics laboratories. Since projectile motion is the two-dimensional version of the free-fall experiment and usually follows the former experiment in such laboratories, it seemed natural to…

Projectile motion is a common phenomenon that is used in introductory physics courses to help students understand motion in two dimensions. Authors have shared a range of ideas for teaching this concept and the associated kinematics in "The Physics Teacher" ("TPT"); however, the "Hoop Challenge" is a new setup not…

I describe an easy-to-build instrument for illustrating the Lorentz force and measuring magnetic fields in introductory physics labs.

The difficulties students have in blending mathematics and physics are here analyzed, by focusing on the issue of a convergent series. We present an experimental and a theoretical analysis of some phenomena which can be investigated employing series, as the bouncing marble and Zeno's paradox of Achilles and the turtle. Measurements were carried…

The typical friction lab performed in introductory mechanics courses is usually not the favorite of either the student or the instructor. The measurements are not all that easy to make, and reproducibility is usually a troublesome issue. This paper describes the augmentation of such a friction lab with a study of the viscous drag on a magnet…

The 1990 film "The Hunt for Red October" (based on Tom Clancy's 1984 debut novel of the same name) featured actors like Sean Connery and Alec Baldwin, but the star of the movie for physicists was a revolutionary new magnetohydrodynamic (MHD) marine propulsion system. The so-called "caterpillar drive" worked with no moving…

Newton's second law is one of the cornerstones of the introductory physics curriculum, but it can still trouble a large number of students well after its introduction, hobbling their ability to apply the concept to problem solving and to related concepts, such as momentum, circular motion, and orbits. While there are several possibilities for…

We describe the use of Apple's iPod touch/iPhone, acting as the pendulum bob, as a means of measuring pendulum period, making use of the device's three-axis digital accelerometer and the freely available SPARKvue app from PASCO scientific. The method can be readily incorporated into an introductory physics laboratory experiment.…

This paper introduces the readers to simple inquiry-based activities (experiments with supporting questions) that one can do with a computer scanner to help students learn and apply the concepts of relative motion in 1 and 2D, vibrational motion and the Doppler effect. We also show how to use these activities to help students think like…

Physics First is offered to ninth graders at high schools in Aurora, CO. A unique new asset of this school system is an embedded research lab called the "Innovation Hyperlab." The goal of the lab is to connect secondary school teaching to ongoing university scientific research, supporting the school district's aim to create opportunities to…

The proper choice of a measurement technique that minimizes systematic and random uncertainty is an essential part of experimental physics. These issues are difficult to teach in the introductory laboratory, though. Because most experiments involve only a single measurement technique, students are often unable to make a clear distinction between…

In introductory physics, students learn that an object tossed upward has a constant downward acceleration while going up, at the highest point and while falling down. To demonstrate this concept, a self-propelled fan cart system is used on a frictionless track. A quick push is given to the fan cart and it is allowed to move away on a track under…