The problem of the discharge time of a cylindrical bucket with a hole in the bottom is solved by means of Bernoulli's equation for non-steady flow.Comparison of the results with experiment and with a simplified analysis using Torricelli's law is made. The measurements were made by high-school students in a laboratory session under guidance of instructors. It is noted that, for large ratios between the radius R of the cylinder and the radius r of the hole, the simple formula for the discharge time of a leaking bucket found by means of Torricelli's law can be used to interpret the experimental results, provided effective parameters for the model are defined.

We show that some results in the kinematics of a point particle can be easily recalled by introducing simple definitions. In particular, in the parabolic motion of a particle thrown from a height h above the origin O at an angle θ from the horizontal direction, the optimum angle θ* for reaching the maximum distance Rmax on the ground, measured from the origin, can be found by calculating the inverse tangent of the ratio between the initial velocity V0 and the final velocity Vf. The value of Rmax is itself found to be easily expressed as V0Vf/g, g being the acceleration due to gravity.

We present a kinematics problem in the framework of a videogame. Students are asked to find possible extensions of a safety zone on the x -axis to the right of an indestructible defense wall of height h placed at x = d in which the point-like balls, fired by strange attackers from the origin O of an Oxy reference system, cannot fall. We solve this problem analytically and suggest generalizations. This exercise may be appealing to students who play videogames, since it is proposed by recalling typical situations in simple virtual reality

In recent years, Modern Physics has been included in the curricula of Italian secondary schools, so that many teachers are asking for specific didactical tools to allow their students to acquire the right skills to deal with final examinations. The Physics Department at University of Salerno (Italy) is, therefore, planning PLS (Piano Lauree Scientifiche / Scientific Degree Project) training courses to give some valid educational paths through new didactical strategies for Physics learning. Introducing quantum mechanics by experimental set-ups with commonly used materials is a rather interesting and challenging task. In fact, this practice allows teacher attending the course to reproduce the same experiments in their own class. Moreover, by using readily available material for the experimental set-up, a soft approach to Modern Physics can be achieved. In the present work, we propose the analysis of an experiment: the measurement of Planck’s constant, one of the most important fundamental quantities in Modern Physics, by means of Light Emitting Diodes (LEDs). The properties of LEDs can be explained by means of elementary quantum mechanics concepts. As a consequence, when describing the quantum behaviour of these commonly used physical systems, Planck’s constant needs to be considered. Therefore, to illustrate one possible way of measuring Planck’s constant to high-school students, we can make use of the current-voltage (I-V) characteristics of a LED. In fact, by opportunely interpreting the measured I-V curves of these systems, by means of a linear fitting the value of Planck’s constant can be obtained.

The dynamics of an ideal fluid contained in two communicating vessels is studied. Despite the fact that the static properties of this system have been known since antiquity, the knowledge of the dynamical properties of an ideal fluid flowing in two communicating vessels is not similarly widespread. By means of Bernoulli's equation for non-stationary fluid flow, we study the oscillatory motion of the fluid when dissipation can be neglected. Palavras-chave: Bernoulli's equation, non-stationary fluid, fluid dynamics Estuda-se a dinâmica de um fluido ideal contido dentro de dois vasos comunicantes. Embora as propriedades estáticas desse sistema sejam conhecidas desde a Antiguidade, são bem menos conhecidas as propriedades dinâmicas do fluxo de dois fluidos ideais contidos vasos comunicantes. Utilizando a equação de Bernoulli para um fluxo não estacionário, nós estudamos o movimento oscilatório do fluido na ausência de dissipação.

The dynamics of water micro-particles in air can be studied by introducing a viscous force in the equations of the motion, in addition to the weight of the particle and the buoyance force. In this work, by taking account of the buoyance force, the range of the micro-particle is calculated as a function of the angle at which it is released. An analytic-numerical procedure to find the angle giving the maximum range is indicated. The effect of a convective air flow is finally studied.

The equation of the motion of a point charge q repelled by a fixed point-like charge Q is derived and studied. In solving this problem useful concepts in classical and relativistic kinematics, in Newtonian mechanics and in non-linear ordinary differential equations are revised. The validity of the approximations is discussed from the physical point of view. In particular the classical electron radius emerges naturally from the requirement that the initial distance is large enough for the non-relativistic approximation to be valid. The relevance of this topic for undergraduate physics teaching is pointed out.

A student realizes that a point particle that is able to rise at a given point P 0 at height H when launched vertically from the origin O of a Cartesian plane at a fixed initial speed V 0 cannot reach, by means of a direct shot from a small spring cannon, a point P positioned at the same height H and distance d from P 0 , with < ≤ d R 0, where R is the maximum horizontal distance attainable with an optimum throw at an angle of 45°. However, the student realizes that, in the absence of air resistance, conservation of energy does not prevent this possibility. Therefore, in order to reach point P, the student uses a perfectly reflecting surface, opportunely inclined with respect to the horizontal. The full story of how this is done will be narrated in this article.