8.01 Classical Mechanics Chapter
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Forces and Motion
Forces and Motion Forces and motion are very important. You may not know but forces are used in everyday life for example: walking, pushing and pulling. Forces cause things to move. Motion is simply a movement but it needs a force to move. There are two types of forces contact force and non-contact force. Contact force is simply two interacting objects touching for example: throwing a ball. Non-contact force is when two objects are not touching are not touching like the moon and the earth ocean Force Firstly, force is just a technical word push or pull. If you push or pull on an object you are applying a force. Secondly, forces make things move or change their motion. There are so many types of forces here are just a few, gravity and magnetism. Different Forces There are two types of forces. Firstly, there is contact force. This is when two interacting objects are physically touching, for example: throwing a ball, when you throw a ball you use friction to push the pall out of your hands. Secondly, the next force is at a distance force. It is when two interacting objects not touching each other like for example: magnets and a paper clip and the moons gravity and the earth ocean. This occurring because of the gravity and magnetism Contact force Contact force is when you are needing to physically touch another object to allow it to move. There are 4 types of contact forces. Firstly normal force is when nothing is occurring, for example: a book on a table. -
Forces Different Types of Forces
Forces and motion are a part of your everyday life for example pushing a trolley, a horse pulling a rope, speed and acceleration. Force and motion causes objects to move but also to stay still. Motion is simply a movement but needs a force to move. There are 2 types of forces, contact forces and act at a distance force. Forces Every day you are using forces. Force is basically push and pull. When you push and pull you are applying a force to an object. If you are Appling force to an object you are changing the objects motion. For an example when a ball is coming your way and then you push it away. The motion of the ball is changed because you applied a force. Different Types of Forces There are more forces than push or pull. Scientists group all these forces into two groups. The first group is contact forces, contact forces are forces when 2 objects are physically interacting with each other by touching. The second group is act at a distance force, act at a distance force is when 2 objects that are interacting with each other but not physically touching. Contact Forces There are different types of contact forces like normal Force, spring force, applied force and tension force. Normal force is when nothing is happening like a book lying on a table because gravity is pulling it down. Another contact force is spring force, spring force is created by a compressed or stretched spring that could push or pull. Applied force is when someone is applying a force to an object, for example a horse pulling a rope or a boy throwing a snow ball. -
Ground Reaction Force Prediction During Weighted Leg Press and Weighted Squat in a Flywheel Exercise Device
DEGREE PROJECT IN MEDICAL ENGINEERING, SECOND CYCLE, 30 CREDITS STOCKHOLM, SWEDEN 2017 Ground Reaction Force Prediction during Weighted Leg Press and Weighted Squat in a Flywheel Exercise Device Estimering av markreaktionskraften vid viktad benpress och viktad knäböj i ett svänghjulsbaserat träningsredskap TOBIAS MUNKHAMMAR KTH ROYAL INSTITUTE OF TECHNOLOGY SCHOOL OF TECHNOLOGY AND HEALTH Acknowledgement First of I would like to thank my supervisor, Maria J¨onsson,for guidance and encouragement during the whole project and Lena Norrbrand, who, together with Maria collected all experi- mental data used in this study. Furthermore, my thanks goes to Rodrigo Moreno, Jan H¨ornfeldt, Jonathan Munkhammar and Ola Eiken for proof-reading and general feedback on the report and Elena Gutierrez Farewik, for being a link towards the musculoskeletal software company whenever the licence struggled. Lastly, I would like to thank all people at the Department of Environmental Physiology, for making me feel welcome and showing interest in my work. Abstract When performing a biomechanical analysis of human movement, knowledge about the ground reaction force (GRF) is necessary to compute forces and moments within joints. This is important when analysing a movement and its effect on the human body. To obtain knowledge about the GRF, the gold standard is to use force plates which directly measure all three components of the GRF (mediolateral, anteroposterior and normal). However, force plates are heavy, clunky and expensive, setting constraints on possible experimental setups, which make it desirable to exclude them and instead use a predictive method to obtain the full GRF. Several predictive methods exist. The node model is a GRF predictive method included in a musculoskeletal modeling software. -
SMU PHYSICS 1303: Introduction to Mechanics
SMU PHYSICS 1303: Introduction to Mechanics Stephen Sekula1 1Southern Methodist University Dallas, TX, USA SPRING, 2019 S. Sekula (SMU) SMU — PHYS 1303 SPRING, 2019 1 Outline Conservation of Energy S. Sekula (SMU) SMU — PHYS 1303 SPRING, 2019 2 Conservation of Energy Conservation of Energy NASA, “Hipnos” by Molinos de Viento and available under Creative Commons from Flickr S. Sekula (SMU) SMU — PHYS 1303 SPRING, 2019 3 Conservation of Energy Key Ideas The key ideas that we will explore in this section of the course are as follows: I We will come to understand that energy can change forms, but is neither created from nothing nor entirely destroyed. I We will understand the mathematical description of energy conservation. I We will explore the implications of the conservation of energy. Jacques-Louis David. “Portrait of Monsieur de Lavoisier and his Wife, chemist Marie-Anne Pierrette Paulze”. Available under Creative Commons from Flickr. S. Sekula (SMU) SMU — PHYS 1303 SPRING, 2019 4 Conservation of Energy Key Ideas The key ideas that we will explore in this section of the course are as follows: I We will come to understand that energy can change forms, but is neither created from nothing nor entirely destroyed. I We will understand the mathematical description of energy conservation. I We will explore the implications of the conservation of energy. Jacques-Louis David. “Portrait of Monsieur de Lavoisier and his Wife, chemist Marie-Anne Pierrette Paulze”. Available under Creative Commons from Flickr. S. Sekula (SMU) SMU — PHYS 1303 SPRING, 2019 4 Conservation of Energy Key Ideas The key ideas that we will explore in this section of the course are as follows: I We will come to understand that energy can change forms, but is neither created from nothing nor entirely destroyed. -
Physics 101 Today Chapter 5: Newton's Third
Physics 101 Today Chapter 5: Newton’s Third Law First, let’s clarify notion of a force : Previously defined force as a push or pull. Better to think of force as an interaction between two objects. You can’t push anything without it pushing back on you ! Whenever one object exerts a force on a second object, the second object exerts an equal and opposite force on the first. Newton’s 3 rd Law - often called “action-reaction ” Eg. Leaning against a wall. You push against the wall. The wall is also pushing on you, equally hard – normal/support force. Now place a piece of paper between the wall and hand. Push on it – it doesn’t accelerate must be zero net force. The wall is pushing equally as hard (normal force) on the paper in the opposite direction to your hand, resulting in zero Fnet . This is more evident when hold a balloon against the wall – it is squashed on both sides. Eg. You pull on a cart. It accelerates. The cart pulls back on you (you feel the rope get tighter). Can call your pull the “ action ” and cart’s pull the “ reaction ”. Or, the other way around. • Newton’s 3 rd law means that forces always come in action -reaction pairs . It doesn’t matter which is called the action and which is called the reaction. • Note: Action-reaction pairs never act on the same object Examples of action-reaction force pairs In fact it is the road’s push that makes the car go forward. Same when we walk – push back on floor, floor pushes us forward. -
2 Simple Machines
Name Class Date CHAPTER 13 Work and Energy SECTION 2 Simple Machines KEY IDEAS As you read this section, keep these questions in mind: • What are simple machines? • What simple machines are in the lever family? • What simple machines are in the inclined plane family? • What are compound machines? What Are Simple Machines? We are surrounded by many different electronics and READING TOOLBOX machines. In physics, a machine is a mechanical device Compare As you read that changes the motion of an object. Remember that this section, make a chart machines make work easier by changing the way a force showing the similarities and is applied. Many machines, such as cars and bicycles, differences between the six simple machines. Describe are complicated. However, even the most complicated how each machine affects machine is made from a combination of just six simple input and output forces machines. Simple machines are the most basic machines. and distances. Include the Scientists divide the six simple machines into two fam- mechanical advantage each machine provides. ilies: the lever family and the inclined plane family. The lever family includes the simple lever, the pulley, and the wheel and axle. The inclined plane family includes the simple inclined plane, the wedge, and the screw. The lever family Simple lever Pulley EHHDBG@<EHL>K Wheel and axle 1. Infer What do you think The is the reason that the wedge inclined and the simple inclined plane plane are in the same family of simple machines? family Screw Simple inclined Wedge plane How Do Levers Work? If you have ever used a claw hammer to remove a nail from a piece of wood, you have used a simple lever. -
Sliding and Rolling: the Physics of a Rolling Ball J Hierrezuelo Secondary School I B Reyes Catdicos (Vdez- Mdaga),Spain and C Carnero University of Malaga, Spain
Sliding and rolling: the physics of a rolling ball J Hierrezuelo Secondary School I B Reyes Catdicos (Vdez- Mdaga),Spain and C Carnero University of Malaga, Spain We present an approach that provides a simple and there is an extra difficulty: most students think that it adequate procedure for introducing the concept of is not possible for a body to roll without slipping rolling friction. In addition, we discuss some unless there is a frictional force involved. In fact, aspects related to rolling motion that are the when we ask students, 'why do rolling bodies come to source of students' misconceptions. Several rest?, in most cases the answer is, 'because the didactic suggestions are given. frictional force acting on the body provides a negative acceleration decreasing the speed of the Rolling motion plays an important role in many body'. In order to gain a good understanding of familiar situations and in a number of technical rolling motion, which is bound to be useful in further applications, so this kind of motion is the subject of advanced courses. these aspects should be properly considerable attention in most introductory darified. mechanics courses in science and engineering. The outline of this article is as follows. Firstly, we However, we often find that students make errors describe the motion of a rigid sphere on a rigid when they try to interpret certain situations related horizontal plane. In this section, we compare two to this motion. situations: (1) rolling and slipping, and (2) rolling It must be recognized that a correct analysis of rolling without slipping. -
Coupling Effect of Van Der Waals, Centrifugal, and Frictional Forces On
PCCP View Article Online PAPER View Journal | View Issue Coupling effect of van der Waals, centrifugal, and frictional forces on a GHz rotation–translation Cite this: Phys. Chem. Chem. Phys., 2019, 21,359 nano-convertor† Bo Song,a Kun Cai, *ab Jiao Shi, ad Yi Min Xieb and Qinghua Qin c A nano rotation–translation convertor with a deformable rotor is presented, and the dynamic responses of the system are investigated considering the coupling among the van der Waals (vdW), centrifugal and frictional forces. When an input rotational frequency (o) is applied at one end of the rotor, the other end exhibits a translational motion, which is an output of the system and depends on both the geometry of the system and the forces applied on the deformable part (DP) of the rotor. When centrifugal force is Received 25th September 2018, stronger than vdW force, the DP deforms by accompanying the translation of the rotor. It is found that Accepted 26th November 2018 the translational displacement is stable and controllable on the condition that o is in an interval. If o DOI: 10.1039/c8cp06013d exceeds an allowable value, the rotor exhibits unstable eccentric rotation. The system may collapse with the rotor escaping from the stators due to the strong centrifugal force in eccentric rotation. In a practical rsc.li/pccp design, the interval of o can be found for a system with controllable output translation. 1 Introduction components.18–22 Hertal et al.23 investigated the significant deformation of carbon nanotubes (CNTs) by surface vdW forces With the rapid development in nanotechnology, miniaturization that were generated between the nanotube and the substrate. -
Rokenbok Snapstack Student Engineering Workbook
Inclined Plane v2.0 Progression: Applications in Design & Engineering - Section 1 Student Engineering Workbook Team Members: Total Points 1. 3. Workbook: /22 pts 2. 4. Challenge: /30 pts Key Terms Write the definitions of each key term in the space provided. 1. Simple Machine: 2. Inclined Plane: 3. Rise: 4. Mechanical Advantage: 5. Force: 6. Work: 7. Effort: 8. Load: 1 Learn, Build & Modify Elements of an Inclined Plane There are two basic elements of an inclined plane. Identify the correct element in the spaces provided. 9. 10. 9. 10. Purpose of an Inclined Plane Fill in the blanks below. 11. Purpose: 12. The inclined plane makes work easier by __________________ the amount of effort that must be applied to raise or lower a load. 13. To reduce the amount of effort needed to raise or lower an object in an inclined plane, the length of the slope should be _______________________. (extended or reduced) Build and Modify Place a check in the boxes below as the team completes each step. 14. Build Rokenbok Inclined Plane 15. Test Inclined Plane - Step 1 16. Test Inclined Plane - Step 2 2 Build & Modify Understanding Mechanical Advantage Fill in the blanks in the statements below. 17. Mechanical Advantage exists when the ______________________ force of a machine is _____________________ than the ____________________ force that was applied to it. 18. For a machine to create mechanical advantage, it must trade increased time or ____________________ for reduced effort. Mechanical Advantage in an Inclined Plane Use the formula for calculating mechanical advantage to solve the Example 1 - Inclined Plane problems below. -
Chapter 8 Glossary
Technology: Engineering Our World © 2012 Chapter 8: Machines—Glossary friction. A force that acts like a brake on moving objects. gear. A rotating wheel-like object with teeth around its rim used to transmit force to other gears with matching teeth. hydraulics. The study and technology of the characteristics of liquids at rest and in motion. inclined plane. A simple machine in the form of a sloping surface or ramp, used to move a load from one level to another. lever. A simple machine that consists of a bar and fulcrum (pivot point). Levers are used to increase force or decrease the effort needed to move a load. linkage. A system of levers used to transmit motion. lubrication. The application of a smooth or slippery substance between two objects to reduce friction. machine. A device that does some kind of work by changing or transmitting energy. mechanical advantage. In a simple machine, the ability to move a large resistance by applying a small effort. mechanism. A way of changing one kind of effort into another kind of effort. moment. The turning force acting on a lever; effort times the distance of the effort from the fulcrum. pneumatics. The study and technology of the characteristics of gases. power. The rate at which work is done or the rate at which energy is converted from one form to another or transferred from one place to another. pressure. The effort applied to a given area; effort divided by area. pulley. A simple machine in the form of a wheel with a groove around its rim to accept a rope, chain, or belt; it is used to lift heavy objects. -
3657 SIMPLE MACHINES: INCLINED PLANE, WEDGE and SCREW Grade Levels: 7-12 15 Minutes CAMBRIDGE EDUCATIONAL 1998
#3657 SIMPLE MACHINES: INCLINED PLANE, WEDGE AND SCREW Grade Levels: 7-12 15 minutes CAMBRIDGE EDUCATIONAL 1998 DESCRIPTION Uses animated graphics and real examples to illustrate an inclined plane, wedge, and screw. Offers a definition of each and examines the relationship between the three. Shows how they have been used historically. Also defines simple machines and mechanical advantage. Reviews main concepts. ACADEMIC STANDARDS Subject Area: Science ¨ Standard: Understands motion and the principles that explain it · Benchmark: Knows the relationship between the strength of a force and its effect on an object (e.g., the greater the force, the greater the change in motion; the more massive the object, the smaller the effect of a given force) · Benchmark: Knows that when a force is applied to an object, the object either speeds up, slows down, or goes in a different direction Subject Area: Historical Understanding ¨ Standard: Understands and knows how to analyze chronological relationships and patterns · Benchmark: Knows how to construct time lines in significant historical developments that mark at evenly spaced intervals the years, decades, and centuries · Benchmark: Knows how to identify patterns of change and continuity in the history of the community, state, and nation, and in the lives of people of various cultures from times long ago until today AFTER SHOWING 1. Point out objects in the classroom that incorporate inclined planes, wedges and screws. 2. Dissect a toy or household gadget. Record progress in science notebooks with written notations and drawings. Identify each part as to type of simple machine and function. 3. Study the history of simple machines. -
Electrostatics
Electrostatics Electrostatics - the study of electrical charges that can be collected and held in one place - charges at rest. Examples: BASIC IDEAS: Electricity begins inside the atom itself. An atom is electrically neutral; it has the same number of protons (+) as it does electrons (-). Objects are charged by adding or removing electrons (charged atom = ion) Fewer electrons than protons = (+) charge occurs More electrons than protons = (-) charge occurs There are two types of charges: positive (+) and negative (-). Like charges repel one another: (+) repels (+), (-) repels (-). Opposite charges attract one another: (+) attracts (-), (-) attracts (+). Charge is quantized Charge is conserved Quantization of Charge The smallest possible amount of charge is that on an electron or proton. This amount is called the fundamental or elementary charge. -19 An electron has charge: qo = -1.602 x 10 C -19 A proton has charge: qo = 1.602 x 10 C Any amount of charge greater than the elementary charge is an exact integer multiple of the elementary charge. q = nqo , where n is an integer For this reason, charge is said to be “quantized”. It comes in quantities of 1.602 x 10-19 C Law of Conservation of Electric Charge The net amount of electric charge produced in any process is zero. Net amount of charge in an isolated system stays constant. Insulators vs. Conductors NOTE: Both insulators and conductors possess charge. Conductor (Metallic Bonds - free valence e’s in outer shell) substance that allows electrons to move easily throughout (sea of electrons) ex. Silver, copper, Al, humid air Insulator (Covalent Bonds - no free e’s in outer shell) substance that does not allow electrons to move freely; electron movement is restricted ex.