The purpose of this paper is to introduce students of science and engineering to the orbital lifetimes of satellites in circular low Earth orbits. It is only necessary to know about classical mechanics for this calculation. The orbital decay of satellites is due to the interaction of the satellite with the surrounding gas, atmospheric drag.…

Experiments are described on collisions between two billiard balls and between a bat and a ball. The experiments are designed to extend a student's understanding of collision events and could be used either as a classroom demonstration or for a student project.

A simple mathematical formulation of Mach's principle is given based on a century of investigation into inertia, and used to check the results of Newton's famous bucket experiment.

This paper examines the common confusion associated with the meaning of mass encountered in modern textbooks, and describes some of the misconceptions to be found in the teaching of mechanics. A new teaching approach is suggested, which may provide a more logical basis for these important ideas.

This paper gives the solution and analysis of projectile motion in a vacuum if the launch and impact heights are not equal. Formulas for the maximum horizontal range and the corresponding angle are derived. An Excel application that simulates the motion is also presented, and the result of an experiment in which 38 secondary school students…

Trampolines can be found in many gardens and also in some playgrounds. They offer an easily accessible vertical motion that includes free fall. In this work, the motion on a trampoline is modelled by assuming a linear relation between force and deflection, giving harmonic oscillations for small amplitudes. An expression for the cycle-time is…

Entertaining and educational experiments that can be conducted in a water park, illustrating physics concepts, principles and fundamental laws, are described. These experiments are suitable for students ranging from senior secondary school to junior university level. Newton's laws of motion, Bernoulli's equation, based on the…

The history of science remembers more than just formal facts about scientific discoveries. These side stories are often inspiring. One of them, the story of an unfulfilled death wish of Jacob Bernoulli regarding spirals, inspired us to look around ourselves. And we saw natural spirals around us, which led to the creation of a Hooke's…

Tablet computers were used as experimental tools to record and analyse the motion of a ball thrown vertically from a moving skateboard. Special applications plotted the measurement data component by component, allowing a simple determination of initial conditions and "g" in order to explore the underlying laws of motion. This experiment…

Friction is an important phenomenon in everyday life. All children are familiar with playground slides, which may thus be a good starting point for investigating friction. Motion on an inclined plane is a standard physics example. This paper presents an investigation of friction by a group of 11-year olds. How did they plan their investigations?…

Some apparently confusing aspects of Newton's laws as applied to an aircraft in normal horizontal flight are neatly resolved by a careful analysis of force, momentum, energy and power. A number of related phenomena are explained at the same time, including the lift and induced drag coefficients, used empirically in the aviation industry.

After a brief history of the Levitron, the first horizontal axis Levitron is reported. Because it is easy to operate, it lends itself to educational physics experiments and analogies. Precession and nutation are visualized by reflecting the beam from a laser pointer off the "spignet". Precession is fundamental to nuclear magnetic…

The hydraulic impulse pump utilizes a fraction of the momentum of a flowing stream to lift a small portion of that water to a higher level. There it may be accumulated in an elevated cistern to provide sufficient water for several families, for the pump works 24 h a day with no additional source of energy. The operation of the pump is described,…

It is hard to observe relativistic effects in everyday life. However, table experiments using a mechanical transmission line for solitons may be an efficient and simple way to show effects such as Lorentz contraction in a classroom. A kink soliton is a deformation of a lattice of several dozen or more pendulums placed on a wire and connected by a…

This paper describes how a microphone plugged in to a normal computer can be used to record the impacts of a ball bouncing on a table. The intervals between these impacts represent the "time of flight" of the ball. Since some energy is lost in each rebound, the time intervals get progressively smaller. Through calculation it is possible…