In high school, and also in introductory physics courses in higher levels of schooling, the law of universal gravitation of planets is introduced by postulating Johannes Kepler's three laws, and later Isaac Newton's law of the inverse of the square of the distance to the Sun. The justification of the laws is only achieved in advanced courses in…

Experimental results are presented concerning the motion of a ball that bounces up an incline a few times then bounces back down again. The number of bounces up the incline is typically small since the speed of the ball in a direction parallel to the incline decreases rapidly, not only during each bounce but also while the ball is in the air. The…

A common homework problem in many introductory physics courses is similar to the following. "A car drives at constant speed over a hill on a road in the shape of a vertical circular arc. What is the maximum speed the car can have and not lose contact with the road at the crest of the hill?" Unfortunately this problem is flawed, because…

The authors investigated the kinematic characteristics of the standing long jump in preschool children. Sixty 4-year-old children (boys: 30 and girls: 30) and sixty 5-year-old children (boys: 30 and girls: 30) participated in the present study. The authors focused on three differences in kinematics: between 4- and 5-year-old children, between boys…

Resonance is an important, and rather dramatic, phenomenon in physics. The mechanical case of a mass-spring oscillator is generally the first example that students encounter in introductory courses. In electromagnetism, the resonance in driven RLC circuits is presented in analogy with mechanics, since the mathematical equations describing them are…

Pitching velocity is a crucial factor in effective baseball pitching performance. Upper-body-focused training is prevalent in baseball training to increase pitching velocity. However, significant pitchers, including youth league baseball players, suffer from upper body injuries due to the heavy training load of the throwing arm. This article…

When thinking about measurement uncertainty in a laboratory experiment that features quantum mechanical effects, it is important to consider both the physical principles of underlying quantum theory (e.g., the uncertainty due to quantum mechanical superposition states) as well as the limitations of the measurement (e.g., the spread in outcomes due…

The aim of this study is to investigate the differences in kinematic parameters of freestyle swimming with respect to young swimmers before and after 3x200 metres (m) performances. Seven male swimmers (mean age: 13.86±0.90; mean height: 164.79±6.89cm; mean mass: 54±5.54kg) participated in this study as volunteers without any injury history. Before…

Hooke's law for springs, stating that the force needed to extend or compress a spring by some distance is proportional to that distance, is a topic covered by almost all introductory physics courses at both school and university levels. In this article we present a much more efficient and intuitive approach, compared to the traditional method, for…

In the context of quantum mechanics, students are often asked to use delta functions to solve problems. Here, we investigate three typical problem-solving processes using delta functions: a delta function potential well problem, a position space delta function problem, and a momentum space delta function problem. We studied students'solutions in…

We have investigated the motion of water flow through glass tubes of different shapes by calculating the value of the Reynolds number denoted as Re. We know that at a given flow rate the value of Re determines the type of flow being classified as laminar, transitional or tubulent. The dependence of Re in different configurations of glass tubes as…

Statistical mechanics has received limited attention in physics education research and remains a relatively underrepresented topic even in research on upper-division physics courses. The purpose of this study was to explore potential challenges that physics students encounter when they solve statistical mechanics problems in groups. Adopting a…

A rocket in free space accelerates from rest by continuously expelling fuel; as its speed increases, its mass decreases. At what speed (and remaining mass) does the rocket carry maximum momentum? Maximum kinetic energy? The answers provide insights into the dynamics of variable-mass systems, and have applications to planetary defense that are…

In a traditional teaching approach, a physics course begins with mechanics, and generally the braking effect due to magnetic interactions is not mentioned among the various types of friction presented (static, sliding, rolling) because students will discover magnetism only in later chapters. In our didactic experience this traditional choice is…

One of the easily accessible results in elementary fluid mechanics is the so-called Torricelli's theorem (or law), which states that the velocity U[subscript th] of the fluid exiting from an orifice at depth "h" from the free surface of a container filled with fluid, is the same as the velocity of a free-falling body from rest over a…