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…

Drop Tower Physics (DTP) is composed of a set of experiments using standard physics lecture demonstration equipment, such as a pendulum, mass spring oscillator, and so forth, while videotaping them as they fall freely in the Dryden Drop Tower in Portland, OR. An article published in "The Physics Teacher" illustrated the behavior of a…

Water rockets can be used in a variety of ways, from schools to planetariums, with very young kids or adults. We propose here simple forms to work with water rockets, going one step further than a simple launch. A smartphone can be used to film the launch and analyze its motion with video analysis or it can even be attached to the rocket, using…

The image of free-falling bar has been recorded to study the effect of the motion on its observed length. This moving bar image is analysed using the Tracker software to determine its length and the end bar's position. An elongated appearance of the bar has been observed with movement. This effect relies on the speed and the exposure time during…

A solid ball placed on a rotating turntable is known to roll slowly around a circular path, at a speed 3.5 times slower than the turnable itself. If the ball is located in a straight track across a diameter of the turntable, then it accelerates rapidly to the edge. Both effects were filmed in slow motion using a video camera and a cake decoration…

Chaotic phenomena are not part of standard curricula, although this subject offers several interesting aspects which can help students better understand basic features of science. A central observation is that even simple physical systems, if chaotic, are unpredictable, just like the weather. We present the principles applied when developing a…

Large drop towers let you experience a couple of seconds of nearly free fall before stopping gracefully in magnetic brakes or bouncing a number of times on compressed air, as in the Turbo Drop tower considered in this work, where many complementary representations are used. An accelerometer taken along on the ride captured the forces experienced…

Newton's cradle is a well-known physics toy that is commonly used by teachers to demonstrate conservation laws in mechanics. It can also be used to investigate the physics of colliding objects, by recording motion of the balls on video film. Various experiments are described using 3-ball and 5-ball cradles, showing how different types of collision…

The vertical bounce of a plastic egg was investigated by dropping the egg on a horizontal surface and filming the result with a video camera. If the egg is dropped on one end then it bounces just like a spherical ball. If the top end of the egg is pointing forwards or backwards when it lands on the surface, or if the egg is spinning when it lands,…

The air drag constant for different nose shapes of projectiles is determined with the help of a simple method combining a projectile launcher, video tracking technique and spreadsheet computer code for simulating the motion. A projectile launcher with low-cost components is developed to study air drag in projectile motion. The launcher is based on…

Video motion analysis allows tracing trajectories of objects in motion and is an established method in physics education. Tablet computers, with their integrated cameras, offer the opportunity to both record and analyze dynamic motions during experiments on a single device. This enables students to work without transitioning the data between…

The drag effect on a falling ball caused by air is a conventional subject in the most well-known textbooks of classical mechanics and fluid dynamics. Further, there are some papers that employ video analysis to track objects movements in the air making it possible to obtain position data as a function of time and its graphs. However, none of them…

Your body is not a point particle. The nature and direction of the forces counteracting gravity influence your experience of uniform rectilinear motion--as does your own orientation in relation to the force of gravity. Sensors in smartphones or other devices can capture these forces, and help establish a connection between the personal experience…

Simple experiments for which differential equations cannot be solved analytically can be addressed using an effective model that satisfactorily reproduces the experimental data. In this work, the 1D kinematics of a remote-control model (toy) car was studied experimentally and its dynamical equation modelled. In the experiment, maximum power was…

Physics textbook authors commonly introduce the concept of weightlessness (apparent or real) through a "thought experiment" in which a person weighs herself or himself in an elevator. When the elevator falls freely, the spring balance should show zero weight. There is an unresolved controversy about how this "zero reading"…