If a ball rolls in a circular path on a horizontal surface at constant speed then its horizontal rotation axis changes direction with time. A simple experiment is presented showing that the torque applied to the ball is equal to the rate of change of its angular momentum, even though the magnitudes of its angular velocity and angular momentum…

Measurements and calculations are presented showing how the trajectory of an object sliding across an inclined plane varies with the launch and incline angles. The trajectory depends on the magnitude and direction of the sliding friction force. The experiment is easy to set up, can be analysed using a video camera, and would be suitable for a…

Calculations are presented showing that the usual 'faster than g' demonstration has a surprising property. That is, a rod hinged at its bottom end rotates at an exponentially increasing rate until it falls with maximum vertical acceleration, unlike an object that falls freely by gravity alone. If the rod is hinged at its top end and released from…

The purpose of this publication is to present a novel approach to the demonstration of the Dzhanibekov effect. The main idea of our version is to use a lightweight spinning top of a spherical external form but distinct principal moments of inertia floating in the upward flow of air. As a result, the Dzhanibekov effect can be easily demonstrated…

Points near the top end of a falling rod hinged at its bottom end can fall faster than g. If a rod falls on a frictionless surface then the bottom end slides backwards and the centre of mass falls vertically with acceleration less than g. The effect was simulated by mounting a rod on wheels and filming the result with a video camera. The…

The article describes a methodology for studying Fresnel diffraction with the active involvement of students in discussing the results of a demonstration experiment. To create a clearly visible model of Fresnel zones, a centimeter radio wave range was chosen, in which the first zone is about 10 cm in size. This makes visible the created…

The udu is a traditional Nigerian percussion instrument that can be thought of as a Helmholtz resonator with two apertures. We use a simple two-particle mechanical analogue to study the behaviour of such a resonator and find that the model describes quite well the main features of udu acoustics.

In this paper, a very simple and low-cost setup design is described for the Seebeck coefficient measurement of the disc and rod-shaped specimens. The setup has been tested for its reliable working by measuring the Seebeck coefficients of standard samples; measured values match with the literature. The setup can be built with commonly available raw…

Students are well aware that when an electric current flows through a light bulb, it glows. As their grade increases, they have understood that electric current flows because electric charges move. Since the transfer of electric charges is not visible, students have many cognitive difficulties in understanding this process, and teaching materials…

Vector cross product transformations are essential components in general physics. The numerous mnemonic devices catered towards each potential transformation result in confusion, defeating their purpose of reducing learning barriers. Therefore, a general mnemonic device, subject-environment interaction or the subject, is proposed to help students…

The experimental investigation of Newton's law of universal gravitation requires expensive and sensitive equipment. Therefore, it is often not possible to conduct such an experiment within a typical physics class. An alternative is to investigate the universal gravitation law by using simulations. In this paper, we are presenting such an augmented…

The coefficient of restitution (COR) for a collision is usually a number between 0 and 1 depending on whether the collision is completely inelastic, or perfectly elastic or something in between. That is the usual situation for colliding spheres or a ball dropped on a horizontal surface. A different situation arises when a bat collides with a ball.…

Simple energy balance models of planetary systems are of fundamental importance to understanding equilibrium temperatures. Most textbooks that discuss energy balance take a further step and include the effects of an atmosphere on the surface temperature. It is noticeable, however, that in such discussions of planetary surface energy balance some…

In many science and engineering undergraduate programmes, physics courses are fundamental and can be seen as a potential place where students can develop complementary abilities such as the computational thinking process. The present work proposes and describes the learning science and engineering with electronic spreadsheets cycle (LSEESC)…

This article presents a simple, fast, and equally accurate technique for measuring the area of a circle and of an ellipse without using geometric formulas. This therefore, together with the known radius of the circle and the semi-major and semi-minor axes of the ellipse, allows for the calculation of [pi]. The experiment is easy, thrilling, and…