Drawing and using free body diagrams: Why it may be better not to decompose forces

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The topic of force is often considered difficult for students to understand and master. The knowledge and alternative frameworks obtained by students before learning the concept of force in class are difficult to change and hinder their understanding process. However, there is no specific and quality instrument developed to determine the understanding and alternative frameworks of matriculation students in Malaysia for the concept of force. Therefore, this study was conducted to develop a quality test instrument in determining the understanding and alternative frameworks of matriculation students for the concept of force. The Force Concept Assessment Test (FCAT) instrument needs to be ensured for its validity and reliability before it can be used. The FCAT instrument consists of 12 multiple-choice items consisting of five subtopics in the topic of force, namely basic force, free-body diagrams, static and kinetic friction, and the concept and application of Newton's Laws of Motion. The instrument was adapted from the Force Concept Inventory (FCI) and past questions from the Matriculation Program Semester Examination (PSPM). FCI adaptation is needed to ensure only relevant questions related to the force concept in the matriculation level curriculum are selected and improved. Two experts in the field have validated the FCAT instrument in terms of physical content and item content suitability. Several corrections and refinements to the validation results were made before the instrument could be used in this study. This quantitative study was conducted based on a survey design. Item analysis was performed to select valid, fair, and quality items, while invalid items were revised or removed. The sample selection used purposive sampling techniques. A total of 34 matriculation students from a matriculation college in the southern zone were selected as respondents. The data were analyzed using the Rasch Measurement Model through the WINSTEP software. High item reliability was obtained with a value of 0.82 and a separation index of 2.85. In addition, the items in the FCAT instrument also met the reliability aspects in the Rasch Measurement Model in terms of item fit, polarity, and unidimensionality. In conclusion, the Rasch Measurement Model showed that the items in the FCAT instrument have a high level of validity and reliability and can be used to determine the understanding and alternative frameworks of matriculation students in the concept of force.

Background. Engineering students often struggle with physics problem-solving, especially mechanics problems, while teaching mechanics helps students predict motion and force impacts, enabling creative engineering design tasks. Problem-solving in mechanics involves using free-body diagrams, visual aids that identify objects and forces, determine appropriate approaches, and reduce information. The free-body diagram technique is crucial for understanding the principles of mechanics, as it helps distinguish between cause and effect, as well as focusing on the practical implementation of mechanics concepts. Objectives. The current study aimed to examine the impact of free-body diagrams on engineering students’ physics performance at a selected public university in Rwanda, highlighting cognitive load theory and constructivist learning theory’s role in improving problem-solving abilities and understanding mechanics concepts. Materials and methods. A sample of 68 students was purposively selected to participate in this study. Prior to the intervention, engineering students were given a pre-test to evaluate their ability to use free-body diagrams in solving mechanics problems. The experimental group underwent a four-week intervention, during which they were taught to draw free-body diagrams, identify external forces, and find force components. The data was collected through achievement tests and analyzed using Microsoft Excel and IBM SPSS Statistics 25. Results. The study findings revealed that incorporating free-body diagrams into mechanics problem-solving improved significantly (p < 0.001) engineering students’ performance in physics. Conclusions. The study recommends incorporating free-body diagrams into the physics instructional curriculum to enhance student’ understanding of basic subjects, practice problem-solving skills, and offer extra support for struggling students. Further research is needed to ascertain the impact of this approach on other physics fields.

Force is one of the most fundamental concepts in physics, used to describe and explain a wide range of phenomena. Students can use force diagrams to learn about fundamental force concepts and solve problems related to forces. However, a limited study has focused on students’ views in drawing force diagrams. This study aims to explore students’ views about force diagrams while solving physics problems. A qualitative study was conducted to explore students’ views on drawing and using force diagrams when solving force problems, involving 18 physics education students. Before the semi-structured interviews were conducted, the students were given two force problems to solve. All interviews were recorded, transcribed, and coded for analysis. Data from the interview was analyzed using NVivo software. This study identified five themes related to students’ views on force diagrams: purposes, conventions, physics concepts, mathematical concepts, and incomplete diagrams. The most frequently mentioned theme by students was the purpose of drawing force diagrams. Students’ knowledge about force concepts and trigonometry also affected their diagrams. Students had different ways to draw diagrams, either on the dot or on the object, and had reasons for drawing the incomplete force diagrams. These findings suggest that students should possess sufficient knowledge of physics and mathematics to draw force diagrams effectively. Students should also understand when force diagrams are applicable and recognize the advantages of drawing them. This study suggests that to support students' effective understanding of force diagrams, educators should employ appropriate strategies and equip students with the skills to create and utilize force diagrams while learning about force concepts and solving problems.

This review summarizes all studies that compare the effect of a MBSR program to a control group intervention, in which the participants had been randomly allocated to be in either the MBSR group or a control group. The review summarizes the results in two categories. First, where the effect of the MBSR program was compared to an inactive group (either a wait list group or one receiving ordinary care also received by the MBSR group). Second, where MBSR was compared with an alternative active group intervention. Based on this review it is reasonable to consider MBSR a moderately well-documented method for helping adults improve their health and cope better with the challenges and stress that life brings. New research should improve the way the trials are conducted addressing the pitfalls in research on mind-body interventions.

O presente trabalho tem como principal objetivo despertar nos alunos o interesse pela física e seus fenômenos da natureza, de modo que o aluno poderá ter mais curiosidade em observar seu cotidiano, e associar a física à sua vida. As leis de Newton estão bastante presentes no nosso cotidiano, já que elas abordam os conceitos de força e massa. Todos os dias observamos vários tipos de movimento: MRU, MRUV, MCU e etc., movimentos que se alteram a cada instante. Estas alterações no movimento são determinadas pela força resultante e pela massa dos corpos, gerando assim uma aceleração. A lei física responsável pela explicação de tal fenômeno é a segunda lei de Newton. Para a realização desse trabalho, será aplicado um questionário na turma de 1 ano do ensino médio na escola Centro de Ensino Josélia Ramos de Almeida, em São João dos Patos – Maranhão. Os alunos irão observar todos os fenômenos físicos durante sua rotina, no período de uma semana. E em seguida irão associar quais fenômenos estão relacionados com a segunda lei de Newton, podendo assim, compreender que as explicações para muitas atividades realizadas, muitos fenômenos que ocorrem e fazem parte da sua vida cotidiana podem ser explicados pela física. Os resultados obtidos foram satisfatórios, pois os alunos abraçaram o trabalho e se mostraram bastante interessados em participar do mesmo. Eles conseguiram enxergar a física ao seu redor, puderam comprovar que realmente a física faz parte do seu cotidiano.

High School Students’ Conceptual Coherence of Qualitative Knowledge in the Case of the Force Concept

Forces and Motion through the Key Stages

Chapter 3 - Force and Motion

In studying Newton's laws, most teachers expect their students to be able to construct a free-body diagram that shows each of the forces that act on an object whose motion they want students to analyze. However, many students frequently cannot identify the correct number of forces that act on the object, or, having decided that a particular force should be added to the diagram, they cannot accurately identify what object exerts that force. In addition, many students have difficulty implementing Newton's third law and correctly identifying action-reaction pairs of forces as well as internal and external forces. In general students do not have an organized process for creating an abstract free-body diagram given a concrete physical situation. They make educated guesses without any way of knowing if what they have done is correct. The purpose of this article is to describe a tool that has been found to be valuable in helping students address each of these problems.

Newton's Law is a basic concept in physics learning at the high school and college levels, but students' conceptual understanding of the concept is still weak. This study aims to analyze students' difficulties in the concept of Newton's Law by looking at the consistency of students' answers to isomorphic problems. The research method used quantitative research by means of a survey. The respondents were 118 students (58 high school students and 60 MAN students) who had taken the Newton's Law chapter. The research instruments were adapted from the Force Concept Inventory (FCI) and isomorphic multiple-choice question (IMCI) which were validated by two physics experts. The analysis technique uses isomorphic analysis by looking at the consistency of student answers to the concept of Newton's Law. Based on the consistency of the answers, three groups of students’ conceptual understanding were determined, namely the “Understanding” when students were consistently correct on three isomorphic items, “Moderately Understanding” if they were consistently correct on two isomorphic items, and “Not Understanding” if only one answer was correct or did not answer correctly on the isomorphic items. The study found that students' conceptual understanding on all isomorphic items was low. especially in Theme 5 which is about the concept of analyzing the relationship between force and the speed of motion of objects with 97.46% of students having difficulties, and Theme 3 with the concept of action-reaction on Newton's Third Law with 95.76% having difficulties. The recommendation for further research is to apply learning methods to overcome students' difficulties in Newton's Law

The concepts of force and motion are essential material in physics. However, students experience many difficulties in the concept of force in rotational dynamics. This research was conducted to measure students’ concept acquisition of the rotational dynamics through Interactive Demonstration assisted by Free-body diagram. The mixed research method was chosen through the use of test instruments in the forms of 10 multiple-choice with open ended questions. The subjects of the research were 35 students XI IPA Senior High School 2 Sungai Penuh-Indonesia. Students’ concept acquisition was measured before and after the intervention to be analyzed quantitatively. The obtained N-gain score was 0.47, and it showed that there was a moderate improvement in students’ concept acquisition, while the effect size value was 1.82 showing that the intervention strongly affected students’ concept aquisition. The data were also supported by the results of the qualitative analysis of the students’ answers and worksheets given during the intervention process.

Gravitational force is one of the fundamental forces that plays an important role in understanding the interaction between massive objects in the universe. However, in physics education, this concept is often difficult to understand concretely due to the limitations of real experiments. This research purpose to analyse the relationship between mass, distance, and gravitational force using the PhET Gravity Force Lab: Basics interactive simulation, as well as to prove its conformity with Newton's Law of Gravity. The research method used was a virtual experiment with a quantitative descriptive approach. Data was obtained by conducting three stages of experiments, namely observing gravitational force on objects of the same and different masses, the relationship between force and mass at a fixed distance, and the relationship between force and distance at a fixed mass. The results showed that gravitational force increased as the mass of objects increased and decreased significantly when the distance between objects increased. The conclusion of this study was that it proved the theory that gravitational force is directly proportional to the product of the masses of the two objects and inversely proportional to the square of the distance between them, in accordance with Newton's Law of Gravity, and showed that the forces were opposite but equal in magnitude, as described in Newton's Third Law.

Earlier research has shown that after physics instruction, many students have difficulties with the force concept, and with constructing free-body diagrams (FBDs). It has been suggested that treating forces as interactions could help students to identify forces as well as to construct the correct FBDs. While there is evidence that identifying interactions helps students in quantitative problem solving, there is no previous research investigating the effect of a visual-representation tool---an interaction diagram (ID)---on students' ability to identify forces, and to construct the correct FBDs. We present an empirical study conducted in 11 Finnish high schools on students ($n=335$, aged 16) taking their first, mandatory, introductory physics course. The study design involved groups of students having heavy, light, or no use of IDs. The heavy and light ID groups answered eight pairs of ID and FBD questions in various physical contexts and the no ID group answered two of the eight FBD questions. The results indicate that the heavy ID group outperformed both the light and the no ID groups in identifying forces and constructing the correct FBDs. The analysis of these data indicates that the use of IDs is especially beneficial in identifying forces when constructing FBDs.

Cognitive-behavioural interventions for attention deficit hyperactivity disorder (ADHD) in adults.