MOTION AND FORCE: DYNAMICS


 Amos Fisher
 2 years ago
 Views:
Transcription
1 MOTION AND FORCE: DYNAMICS We ve been dealing with the fact that objects move. Velocity, acceleration, projectile motion, etc. WHY do they move? Forces act upon them, that s why! The connection between Force and motion is DYNAMICS. FORCE A push or pull on an object. An object falls due to the force of gravity. Forces do not always give rise to motion.! Spring Scalea device used to measure force! Weighta measure of the FORCE on an object, carries a unit of Newtons (N).! Forcesare vectors that carry a magnitude and direction. NEWTON S FIRST LAW OF MOTION [Law of Inertia] An object in motion remains in motion along a straight line path until a force acts upon that object. An object at rest remains at rest until a force acts upon that object.! Inertiatendency of a body to maintain its state of rest or uniform motion.! Frictiona force that acts against motion! Inertial Reference FrameNewton s first law holds true. Rest a cup on a dashboard in your car before leaving your garageback out of the garage splash! That is NOT an inertial frame of reference!! Massa property; measure of the inertia of a body (kg)! Weighta force; F g = mg measured in Newtons. A word that has a casual meaning on Earth since g is relatively 9.8 m/s 2. Mass and weight have often been used interchangeably during your short lifetime! NEWTON S SECOND LAW OF MOTION [F = ma] The acceleration of an object is directly proportional to the net force acting on it and is inversely proportional to its mass. The direction of the acceleration is in the direction of the net force acting on the object. a = EF m In English: When a net force acts upon an object, it s rest or uniform motion is changed. That means it experiences an acceleration, technically defined as a change in velocity.! E F = ma! E F = net force! Forcean action capable of accelerating an object; measured in Newtons! 1 N = kg Cm/s 2! ONE Dimensional L F = ma! TWO Dimensional L F x = ma x & F y = ma y & F z = ma z
2 Example 4.1 Estimate the net force needed to accelerate a 1000kg car at 1/2 g. Example 4.2 What net force is required to bring a 1500kg car to rest from a speed of 100 km/h within a distance of 55 m? NEWTON S THIRD LAW [actionreaction] Whenever on object exerts a force on a second object, the second object exerts an equal and opposite force on the first object. Often stated, To every action there is an equal and opposite reaction. The second law quantifies how forces affect motion. But, where do forces come from? A force is exerted ON an object and BY another object. Hit a nail with a hammerthe force is applied ON the nail BY the hammer BUT, the nail exerts a force back on the hammer. How do we know? 1) the speed of the hammer is rapidly reduced to zero! 2) this force must be strong to so rapidly reduce the speed of the hammer 3) the nail rarely sinks all the way into the wood on the first try! Example 4.3 What makes a car go forward? Forces 2
3 Example 4.4 Michelangelo s assistant has been assigned the task of moving a block of marble using a sled. He says to his boss, When I exert a forward force on the sled, the sled exerts an equal and opposite force backward, so how can I ever start it moving? No matter how hard I pull, the backward reaction force always equals my forward force, so the net force must be zero. I ll never be able to move this load. Is this a case of a little knowledge being dangerous? Explain. WEIGHTTHE FORCE OF GRAVITY; AND THE NORMAL FORCE! WeightThe force of gravity originates at the center of the Earth. F g = F w = mg always directed downward, toward the center of the Earth.! g9.8 m/s 2 The moon s gravity is 1/6 that of the Earth since the moon s mass is 1/6 that of the Earth s. Your weight on the moon is 1/6 that of your weight here on EarthI find this a pleasant thought! So why don t we go crashing through the floor on to the poor souls below? The force of the floor exerts force right back at ya due to it s elasticity. This force is the normal force and is NOT a case of actionreaction!! Normal force normal means z (usually thought of as z to the motion!). F N! Since E F = 0 for an object at rest and g is acting downward this force often balances the force of weight for a stationary object. Forces 3
4 Example 4.5 A friend has given you a special gift, a box of mass 10.0 kg with a mystery surprise inside. It s a reward for your fine showing on the physics final. The box is resting on a smooth (frictionless) horizontal surface of a table. a) Determine the weight of the box and the normal force acting on it. b) Now your friend pushes down on the box with a force of 40.0 N. Again determine the normal force acting on the box. c) If your friend pulls upward on the box with a force of 40.0 N, what now is the normal force on the box? Notice that the normal force is elastic in origin! THAT S WHY IS NOT AN ACTIONREACTION PAIR WITH THE WEIGHT! Example 4.6 What happens when a person pulls upward on the box in Example 4.5 c) with a force equal to, or greater than, the box s weight, say F p = N rather than the 40.0 N shown in figure 416 c)? Forces 4
5 SOLVING PROBLEMS WITH NEWTON S LAWS: VECTOR FORCES AND FREEBODY DIAGRAMS Net force = vector sum = E F and is % to acceleration of an object Example 4.7 Calculate the sum of the two forces acting on the boat shown in Fig. 419a. FreeBody diagram:! Show all forces acting on EACH object involved! Point masses for now... until we start rotating stuff! Example 4.8 A hockey puck is sliding at constant velocity across a flat horizontal ice surface that is assumed to be frictionless. Which of the sketches is the correct freebody diagram for this puck? What would your answer be if the puck was slowed down? Forces 5
6 Example 4.9 Suppose a friend asks to examine the 10.0 kg box you were given earlier, hoping to guess what s inside. You respond, Sure, pull the box over to you. She then pulls the box over by an attached ribbon/string/cord/rope along the smooth surface of the table. The magnitude of the force exerted by the person is 40.0 N and is exerted at a 30.0 angle with the table top. Calculate a) the acceleration of the box. b) the magnitude of the upward force, F N exerted by the table on the box. Assume that friction can be neglected.! TensionF T when a flexible cord/rope/etc. pulls on an object it is said to be under tension. These can only pull, NOT push since they are flexible pieces of matter! Example 4.10 Two boxes are connected by a lightweight cord and are resting on a table. The boxes have masses of 12.0 kg and 10.0 kg. A horizontal force F p of 40.0 N is applied by a person to the 10.0 kg box. Find a) the acceleration of each box Forces 6
7 b) the tension in the cord. Example 4.11 Two masses suspended over a pulley by a cable is sometimes referred to as an Atwood s machine. Consider the reallife application of an elevator (m 1 ) and its counterweight (m 2 ). To minimize the work done by the motor to raise and lower the elevator safely, m 1 and m 2 are similar in mass. We leave the motor out of the system for this calculation, and assume the cable s mass is negligible and the pulley is frictionless and massless, which assures that the tension, F T, in the cord has the same magnitude on both sides of the pulley. Let the mass of the counterweight be m 2 = 1,000 kg. Assume the mass of the empty elevator is 850 kg, and its mass when carrying 4 passengers is m 1 = 1150 kg. For the latter case (m 1 = 1150 kg), calculate a) the acceleration of the elevator and b) the tension in the cable. Forces 7
8 Example 4.12 Muscleman is trying to lift a piano (slowly) up to a secondstory apartment. He is using a rope looped over two pulleys as shown. How much of the piano s 2000 N weight does he have to pull on the rope? Example 4.13 Finding her car stuck in the mud, a bright graduate student of a good physics course ties a strong rope to the back bumper of the car, and the other end to a tree. She pushes at the midpoint of the rope with her maximum effort, which she estimates to be a force F p. 300 N. The car just begins to budge with the rope at an angle 2 which she estimates to be 5. With what force is the rope pulling on the car? Neglect the mass of the rope. Forces 8
9 APPLICATIONS INVOLVING FRICTION; INCLINES Frictionexists between 2 solid surfaces because even the smoothest looking surface is quite rough on a microscopic scale. When we try to slide an object across another surface, these microscopic bumps impede motion. Additionally, the atoms snuggle up next to one another and have interactions of an attractive nature and can further impede motion. kinetic frictionsliding friction; the friction that persists even once the object is in motion. This force acts opposite to the body s velocity and is determined by the nature of the two surfaces. The force of kinetic friction is approximately proportional to the normal force. [the normal force is the force that either object exerts on the other perpendicular to their common surface of contact] F f % F N insert a proportionality constant and presto, an equals sign appears along with a constant! F f = : K F N : K the coefficient of kinetic friction; its value depends on the nature of the 2 surfaces; it s an approximation since polishing/ sanding, etc. alters the surfaces. This is not a vector equation since the two vectors act z to one another. It is also an experimental relationship NOT a fundamental law. The force of friction depends very little on surface area. It doesn t matter whether you slide your book flat along the table or on its spine along the tableit s frictional force is essentially unaffected. Forces 9
10 Static frictionforce applied to get an object moving; it is always present between 2 stationary objects and increases when the force applied increases until the force applied overpowers the static frictional force and the kinetic frictional force takes over. At the point it begins to move you have applied the maximum force of static friction F MAX # : S F N than get it to move! you ve probably noticed it s easier to keep an object moving Example 4.14 Our 10.0 kg mystery box rests on a horizontal floor. The coefficient of static friction is : s = 0.40 and the coefficient of kinetic friction is : K = Determine the force of friction, F f, acting on the box if a horizontal external applied force F A is exerted on it of magnitue [answer in 2 sig. figs for each part!] a) 0 N b) 10 N c) 20 N d) 38 N e) 40 N Forces 10
11 Notice that BOTH the normal force and the frictional forces are exerted by one surface ON another. F N is perpendicular to the contact surface F f is parallel to the contact surface and in the opposite direction of the x velocity. Example 4.15 Your little sister wants a ride on her sled. If you are on flat ground, will ou exert less force if you push her or pull her? Assume the same angle 2 in each case. Example 4.16 Two boxes are connected by a cord running over a pulley. The coefficient of kinetic friction between box I and the table is We ignore the mass of the cord and pulley and any fricion in the pulley, which means we can assume that a force applied to one end of the cord will have the same magnitude at the other end. We wish to find the acceleration, a, of the system, which will have the same magnitude for both boxes assuming the cord doesn t stretch. As box II moves down, box I moves to the right. Forces 11
12 OBJECTS MOVING ON AN INCLINE Easier to choose the xy coordinate system so that the xaxis is parallel to the incline surface and the yaxis is therefore, perpendicular to the incline. This helps because then a has only one component and if friction is present, two of the forces will have only one component: F f along the plane, opposite ot the object s velocity, and F N which is NOT vertical but is perpendicular to the plane. A picture will help! FN = FW cosθ F = F sinθ = mgsinθ applied W Example 4.17 A skier has just begun descending a 30.0 slope. Assuming the coefficient of kinetic friction is 1.10, a) draw the free body diagram b) calculate her acceleration c) calculate the speed she will reach after 4.0 seconds. Example 4.18 Suppose the snow is slushy and the skier moves down the 30.0 slope at constant speed. Determine the coefficient of friction, : K? Forces 12
Chapter 4 Dynamics: Newton s Laws of Motion. Copyright 2009 Pearson Education, Inc.
Chapter 4 Dynamics: Newton s Laws of Motion Force Units of Chapter 4 Newton s First Law of Motion Mass Newton s Second Law of Motion Newton s Third Law of Motion Weight the Force of Gravity; and the Normal
More informationChapter 4 Dynamics: Newton s Laws of Motion
Chapter 4 Dynamics: Newton s Laws of Motion Units of Chapter 4 Force Newton s First Law of Motion Mass Newton s Second Law of Motion Newton s Third Law of Motion Weight the Force of Gravity; and the Normal
More informationphysics 111N forces & Newton s laws of motion
physics 111N forces & Newton s laws of motion forces (examples) a push is a force a pull is a force gravity exerts a force between all massive objects (without contact) (the force of attraction from the
More informationIsaac Newton (1642 to 1727) Force. Newton s Three Law s of Motion. The First Law. The First Law. The First Law
Isaac Newton (1642 to 1727) Force Chapter 4 Born 1642 (Galileo dies) Invented calculus Three laws of motion Principia Mathematica. Newton s Three Law s of Motion 1. All objects remain at rest or in uniform,
More informationCHAPTER 3 NEWTON S LAWS OF MOTION
CHAPTER 3 NEWTON S LAWS OF MOTION NEWTON S LAWS OF MOTION 45 3.1 FORCE Forces are calssified as contact forces or gravitational forces. The forces that result from the physical contact between the objects
More informationNewton s Laws of Motion
Newton s Laws of Motion FIZ101E Kazım Yavuz Ekşi My contact details: Name: Kazım Yavuz Ekşi Email: eksi@itu.edu.tr Notice: Only emails from your ITU account are responded. Office hour: Wednesday 10.0012.00
More informationMULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
Exam Name MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) The following four forces act on a 4.00 kg object: 1) F 1 = 300 N east F 2 = 700 N north
More informationChapter 4. Forces and Newton s Laws of Motion. continued
Chapter 4 Forces and Newton s Laws of Motion continued 4.9 Static and Kinetic Frictional Forces When an object is in contact with a surface forces can act on the objects. The component of this force acting
More informationWhat is a force? Identifying forces. What is the connection between force and motion? How are forces related when two objects interact?
Chapter 4: Forces What is a force? Identifying forces. What is the connection between force and motion? How are forces related when two objects interact? Application different forces (field forces, contact
More informationGround Rules. PC1221 Fundamentals of Physics I. Force. Zero Net Force. Lectures 9 and 10 The Laws of Motion. Dr Tay Seng Chuan
PC1221 Fundamentals of Physics I Lectures 9 and 10 he Laws of Motion Dr ay Seng Chuan 1 Ground Rules Switch off your handphone and pager Switch off your laptop computer and keep it No talking while lecture
More informationPhysics: Principles and Applications, 6e Giancoli Chapter 4 Dynamics: Newton's Laws of Motion
Physics: Principles and Applications, 6e Giancoli Chapter 4 Dynamics: Newton's Laws of Motion Conceptual Questions 1) Which of Newton's laws best explains why motorists should buckleup? A) the first law
More informationTHE NATURE OF FORCES Forces can be divided into two categories: contact forces and noncontact forces.
SESSION 2: NEWTON S LAWS Key Concepts In this session we Examine different types of forces Review and apply Newton's Laws of motion Use Newton's Law of Universal Gravitation to solve problems Xplanation
More informationChapter 4 Dynamics: Newton s Laws of Motion
Chapter 4 Dynamics: Newton s Laws of Motion Units of Chapter 4 Force Newton s First Law of Motion Mass Newton s Second Law of Motion Newton s Third Law of Motion Weight the Force of Gravity; and the NormalForce
More informationCollege Physics 140 Chapter 4: Force and Newton s Laws of Motion
College Physics 140 Chapter 4: Force and Newton s Laws of Motion We will be investigating what makes you move (forces) and how that accelerates objects. Chapter 4: Forces and Newton s Laws of Motion Forces
More information041. Newton s First Law Newton s first law states: Sections Covered in the Text: Chapters 4 and 8 F = ( F 1 ) 2 + ( F 2 ) 2.
Force and Motion Sections Covered in the Text: Chapters 4 and 8 Thus far we have studied some attributes of motion. But the cause of the motion, namely force, we have essentially ignored. It is true that
More informationNewton s Third Law. object 1 on object 2 is equal in magnitude and opposite in direction to the force exerted by object 2 on object 1
Newton s Third Law! If two objects interact, the force exerted by object 1 on object 2 is equal in magnitude and opposite in direction to the force exerted by object 2 on object 1!! Note on notation: is
More informationChapter 5 Using Newton s Laws: Friction, Circular Motion, Drag Forces. Copyright 2009 Pearson Education, Inc.
Chapter 5 Using Newton s Laws: Friction, Circular Motion, Drag Forces Units of Chapter 5 Applications of Newton s Laws Involving Friction Uniform Circular Motion Kinematics Dynamics of Uniform Circular
More informationLesson 04: Newton s laws of motion
www.scimsacademy.com Lesson 04: Newton s laws of motion If you are not familiar with the basics of calculus and vectors, please read our freely available lessons on these topics, before reading this lesson.
More informationForces. Isaac Newton was the first to discover that the laws that govern motions on the Earth also applied to celestial bodies.
Forces Now we will discuss the part of mechanics known as dynamics. We will introduce Newton s three laws of motion which are at the heart of classical mechanics. We must note that Newton s laws describe
More information1. Newton s Laws of Motion and their Applications Tutorial 1
1. Newton s Laws of Motion and their Applications Tutorial 1 1.1 On a planet far, far away, an astronaut picks up a rock. The rock has a mass of 5.00 kg, and on this particular planet its weight is 40.0
More informationNewton s Laws of Motion
Physics Newton s Laws of Motion Newton s Laws of Motion 4.1 Objectives Explain Newton s first law of motion. Explain Newton s second law of motion. Explain Newton s third law of motion. Solve problems
More information2.1 Force and Motion Kinematics looks at velocity and acceleration without reference to the cause of the acceleration.
2.1 Force and Motion Kinematics looks at velocity and acceleration without reference to the cause of the acceleration. Dynamics looks at the cause of acceleration: an unbalanced force. Isaac Newton was
More informationExplaining Motion:Forces
Explaining Motion:Forces Chapter Overview (Fall 2002) A. Newton s Laws of Motion B. Free Body Diagrams C. Analyzing the Forces and Resulting Motion D. Fundamental Forces E. Macroscopic Forces F. Application
More informationForces & Newton s Laws. Teacher Packet
AP * PHYSICS B Forces & Newton s Laws eacher Packet AP* is a trademark of the College Entrance Examination Board. he College Entrance Examination Board was not involved in the production of this material.
More informationPhysics Notes Class 11 CHAPTER 5 LAWS OF MOTION
1 P a g e Inertia Physics Notes Class 11 CHAPTER 5 LAWS OF MOTION The property of an object by virtue of which it cannot change its state of rest or of uniform motion along a straight line its own, is
More information1) A 2) B 3) C 4) A and B 5) A and C 6) B and C 7) All of the movies A B C. PHYS 11: Chap. 2, Pg 2
1) A 2) B 3) C 4) A and B 5) A and C 6) B and C 7) All of the movies A B C PHYS 11: Chap. 2, Pg 2 1 1) A 2) B 3) C 4) A and B 5) A and C 6) B and C 7) All three A B PHYS 11: Chap. 2, Pg 3 C 1) more than
More informationChapter 5 Newton s Laws of Motion
Chapter 5 Newton s Laws of Motion Sir Isaac Newton (1642 1727) Developed a picture of the universe as a subtle, elaborate clockwork slowly unwinding according to welldefined rules. The book Philosophiae
More informationPhysics I Honors: Chapter 4 Practice Exam
Physics I Honors: Chapter 4 Practice Exam Multiple Choice Identify the letter of the choice that best completes the statement or answers the question. 1. Which of the following statements does not describe
More informationChapter Test. Teacher Notes and Answers Forces and the Laws of Motion. Assessment
Assessment Chapter Test A Teacher Notes and Answers Forces and the Laws of Motion CHAPTER TEST A (GENERAL) 1. c 2. d 3. d 4. c 5. c 6. c 7. c 8. b 9. d 10. d 11. c 12. a 13. d 14. d 15. b 16. d 17. c 18.
More informationPH2213 : Examples from Chapter 4 : Newton s Laws of Motion. Key Concepts
PH2213 : Examples from Chapter 4 : Newton s Laws of Motion Key Concepts Newton s First and Second Laws (basically Σ F = m a ) allow us to relate the forces acting on an object (lefthand side) to the motion
More information5. Forces and MotionI. Force is an interaction that causes the acceleration of a body. A vector quantity.
5. Forces and MotionI 1 Force is an interaction that causes the acceleration of a body. A vector quantity. Newton's First Law: Consider a body on which no net force acts. If the body is at rest, it will
More informationNewton s Laws PreTest
Newton s Laws PreTest 1.) Consider the following two statements and then select the option below that is correct. (i) It is possible for an object move in the absence of forces acting on the object. (ii)
More informationChapter 4  Forces and Newton s Laws of Motion w./ QuickCheck Questions
Chapter 4  Forces and Newton s Laws of Motion w./ QuickCheck Questions 2015 Pearson Education, Inc. Anastasia Ierides Department of Physics and Astronomy University of New Mexico September 8, 2015 Review
More informationPhysics 11 Assignment KEY Dynamics Chapters 4 & 5
Physics Assignment KEY Dynamics Chapters 4 & 5 ote: for all dynamics problemsolving questions, draw appropriate free body diagrams and use the aforementioned problemsolving method.. Define the following
More informationThis week s homework. 2 parts Quiz on Friday, Ch. 4 Today s class: Newton s third law Friction Pulleys tension. PHYS 2: Chap.
This week s homework. 2 parts Quiz on Friday, Ch. 4 Today s class: Newton s third law Friction Pulleys tension PHYS 2: Chap. 19, Pg 2 1 New Topic Phys 1021 Ch 7, p 3 A 2.0 kg wood box slides down a vertical
More informationLecture 6. Weight. Tension. Normal Force. Static Friction. Cutnell+Johnson: 4.84.12, second half of section 4.7
Lecture 6 Weight Tension Normal Force Static Friction Cutnell+Johnson: 4.84.12, second half of section 4.7 In this lecture, I m going to discuss four different kinds of forces: weight, tension, the normal
More informationForces. Lecturer: Professor Stephen T. Thornton
Forces Lecturer: Professor Stephen T. Thornton Reading Quiz: Which of Newton s laws refers to an action and a reaction acceleration? A) First law. B) Second law. C) Third law. D) This is a trick question.
More informationAP Physics Newton's Laws Practice Test
AP Physics Newton's Laws Practice Test Answers: A,D,C,D,C,E,D,B,A,B,C,C,A,A 15. (b) both are 2.8 m/s 2 (c) 22.4 N (d) 1 s, 2.8 m/s 16. (a) 12.5 N, 3.54 m/s 2 (b) 5.3 kg 1. Two blocks are pushed along a
More informationHW#4b Page 1 of 6. I ll use m = 100 kg, for parts bc: accelerates upwards, downwards at 5 m/s 2 A) Scale reading is the same as person s weight (mg).
HW#4b Page 1 of 6 Problem 1. A 100 kg person stands on a scale. a.) What would be the scale readout? b.) If the person stands on the scale in an elevator accelerating upwards at 5 m/s, what is the scale
More informationChapter 5 Newton s Laws of Motion
Chapter 5 Newton s Laws of Motion Force and Mass Units of Chapter 5 Newton s First Law of Motion Newton s Second Law of Motion Newton s Third Law of Motion The Vector Nature of Forces: Forces in Two Dimensions
More informationNewton s Laws of Motion. Chapter 4
Newton s Laws of Motion Chapter 4 Changes in Motion Section 4.1 Force is simply a push or pull It is an interaction between two or more objects Force is a vector so it has magnitude and direction In the
More informationPhysics 101 Prof. Ekey. Chapter 5 Force and motion (Newton, vectors and causing commotion)
Physics 101 Prof. Ekey Chapter 5 Force and motion (Newton, vectors and causing commotion) Goal of chapter 5 is to establish a connection between force and motion This should feel like chapter 1 Questions
More informationv v ax v a x a v a v = = = Since F = ma, it follows that a = F/m. The mass of the arrow is unchanged, and ( )
Week 3 homework IMPORTANT NOTE ABOUT WEBASSIGN: In the WebAssign versions of these problems, various details have been changed, so that the answers will come out differently. The method to find the solution
More informationDynamics Why do objects move as they do? What makes an object at rest, begin to move? What makes a body accelerate or decelerate?
Dynamics Why do objects move as they do? What makes an object at rest, begin to move? What makes a body accelerate or decelerate? What makes an object move in a circle? Force A Force is simply a push
More informationPhysics1 Recitation3
Physics1 Recitation3 The Laws of Motion 1) The displacement of a 2 kg particle is given by x = At 3/2. In here, A is 6.0 m/s 3/2. Find the net force acting on the particle. (Note that the force is time
More informationA) N > W B) N = W C) N < W. speed v. Answer: N = W
CTN12. Consider a person standing in an elevator that is moving upward at constant speed. The magnitude of the upward normal force, N, exerted by the elevator floor on the person's feet is (larger than/same
More informationIf you put the same book on a tilted surface the normal force will be less. The magnitude of the normal force will equal: N = W cos θ
Experiment 4 ormal and Frictional Forces Preparation Prepare for this week's quiz by reviewing last week's experiment Read this week's experiment and the section in your textbook dealing with normal forces
More informationWorksheet #1 Free Body or Force diagrams
Worksheet #1 Free Body or Force diagrams Drawing FreeBody Diagrams Freebody diagrams are diagrams used to show the relative magnitude and direction of all forces acting upon an object in a given situation.
More informationVELOCITY, ACCELERATION, FORCE
VELOCITY, ACCELERATION, FORCE velocity Velocity v is a vector, with units of meters per second ( m s ). Velocity indicates the rate of change of the object s position ( r ); i.e., velocity tells you how
More informationNewton s Law of Motion
chapter 5 Newton s Law of Motion Static system 1. Hanging two identical masses Context in the textbook: Section 5.3, combination of forces, Example 4. Vertical motion without friction 2. Elevator: Decelerating
More informationNewton s Laws of Motion
Chapter 4 Newton s Laws of Motion PowerPoint Lectures for University Physics, Thirteenth Edition Hugh D. Young and Roger A. Freedman Lectures by Wayne Anderson Goals for Chapter 4 To understand the meaning
More informationPHYSICS MIDTERM REVIEW
1. The acceleration due to gravity on the surface of planet X is 19.6 m/s 2. If an object on the surface of this planet weighs 980. newtons, the mass of the object is 50.0 kg 490. N 100. kg 908 N 2. If
More informationChapter 5 Problems. = 9ˆ i + 0 ˆ j F 2 F 1. = 8cos62 ˆ i + 8sin62 ˆ j. = (9 8cos62 ) i ˆ + (8sin62 ) ˆ j = i ˆ ˆ j =
Chapter 5 Problems 5.1 Only two horizontal forces act on a 3.0 kg body. One force is 9.0N, acting due east, and the other is 8.0N act 62 degrees North of west. What is the magnitude of the body s acceleration?
More informationRecap. A force is the product of an object s mass and acceleration. Forces are the reason why objects change their velocity. Newton s second law:
Recap A force is the product of an object s mass and acceleration. Forces are the reason why objects change their velocity. Newton s second law: Unit: 1 N = 1 kg m/s 2 Forces are vector quantities, since
More informationBROCK UNIVERSITY. PHYS 1P21/1P91 Solutions to Midterm test 26 October 2013 Instructor: S. D Agostino
BROCK UNIVERSITY PHYS 1P21/1P91 Solutions to Midterm test 26 October 2013 Instructor: S. D Agostino 1. [10 marks] Clearly indicate whether each statement is TRUE or FALSE. Then provide a clear, brief,
More informationPhysics 1000 Final Examination. December A) 87 m B) 46 m C) 94 m D) 50 m
Answer all questions. The multiple choice questions are worth 4 marks and problems 10 marks each. 1. You walk 55 m to the north, then turn 60 to your right and walk another 45 m. How far are you from where
More informationHow does the net force change between scenario 1 and 2?
How does the net force change between scenario 1 and 2? A) The magnitude decreases, the direction stays the same B) The magnitude stays the same, the direction changes C) The magnitude decreases AND the
More informationPhysics 11 Chapter 4 HW Solutions
Physics 11 Chapter 4 HW Solutions Chapter 4 Conceptual Question: 5, 8, 10, 18 Problems: 3, 3, 35, 48, 50, 54, 61, 65, 66, 68 Q4.5. Reason: No. If you know all of the forces than you know the direction
More informationQ5.1. A. tension T 1 B. tension T 2 C. tension T 3 D. two of the above E. T 1, T 2, and T Pearson Education, Inc.
Q5.1 A car engine is suspended from a chain linked at O to two other chains. Which of the following forces should be included in the freebody diagram for the engine? A. tension T 1 B. tension T 2 C. tension
More informationExample (1): Motion of a block on a frictionless incline plane
Firm knowledge of vector analysis and kinematics is essential to describe the dynamics of physical systems chosen for analysis through ewton s second law. Following problem solving strategy will allow
More informationAP1 Dynamics. Answer: (D) foot applies 200 newton force to nose; nose applies an equal force to the foot. Basic application of Newton s 3rd Law.
1. A mixed martial artist kicks his opponent in the nose with a force of 200 newtons. Identify the actionreaction force pairs in this interchange. (A) foot applies 200 newton force to nose; nose applies
More information56 Chapter 5: FORCE AND MOTION I
Chapter 5: FORCE AND MOTION I 1 An example of an inertial reference frame is: A any reference frame that is not accelerating B a frame attached to a particle on which there are no forces C any reference
More informationPHYSICS 111 HOMEWORK SOLUTION, week 4, chapter 5, sec 17. February 13, 2013
PHYSICS 111 HOMEWORK SOLUTION, week 4, chapter 5, sec 17 February 13, 2013 0.1 A 2.00kg object undergoes an acceleration given by a = (6.00î + 4.00ĵ)m/s 2 a) Find the resultatnt force acting on the object
More informationSerway_ISM_V1 1 Chapter 4
Serway_ISM_V1 1 Chapter 4 ANSWERS TO MULTIPLE CHOICE QUESTIONS 1. Newton s second law gives the net force acting on the crate as This gives the kinetic friction force as, so choice (a) is correct. 2. As
More informationNewton s Laws of Motion
Section 3.2 Newton s Laws of Motion Objectives Analyze relationships between forces and motion Calculate the effects of forces on objects Identify force pairs between objects New Vocabulary Newton s first
More informationObjective: Equilibrium Applications of Newton s Laws of Motion I
Type: Single Date: Objective: Equilibrium Applications of Newton s Laws of Motion I Homework: Assignment (111) Read (4.14.5, 4.8, 4.11); Do PROB # s (46, 47, 52, 58) Ch. 4 AP Physics B Mr. Mirro Equilibrium,
More informationNewton s Laws of Motion
Newton s Laws of Motion Newton s Laws and the Mousetrap Racecar Simple version of Newton s three laws of motion 1 st Law: objects at rest stay at rest, objects in motion stay in motion 2 nd Law: force
More information2. What magnitude of net force is required to give a 135kg refrigerator an acceleration of magnitude 1.40 m/. [189 N]
PAGE 1 OF 14 EMAIL: MIAMIMATHTUTOR@GMAIL.COM CONTACT NUMBER: (786)5564839 PHYSICS I NEWTON S LAWS OF MOTION PRACTICE PROBLEMS 5.1 1. If a net horizontal force of 130 N is applied to a person with mass
More informationPhysics Midterm Review. MultipleChoice Questions
Physics Midterm Review MultipleChoice Questions 1. A train moves at a constant velocity of 90 km/h. How far will it move in 0.25 h? A. 10 km B. 22.5 km C. 25 km D. 45 km E. 50 km 2. A bicyclist moves
More informationChapter 4 Newton s Laws: Explaining Motion
Chapter 4 Newton s s Laws: Explaining Motion Newton s Laws of Motion The concepts of force, mass, and weight play critical roles. A Brief History! Where do our ideas and theories about motion come from?!
More informationLecture Presentation Chapter 4 Forces and Newton s Laws of Motion
Lecture Presentation Chapter 4 Forces and Newton s Laws of Motion Suggested Videos for Chapter 4 Prelecture Videos Newton s Laws Forces Video Tutor Solutions Force and Newton s Laws of Motion Class Videos
More informationPHYS101 The Laws of Motion Spring 2014
The Laws of Motion 1. An object of mass m 1 = 55.00 kg placed on a frictionless, horizontal table is connected to a string that passes over a pulley and then is fastened to a hanging object of mass m 2
More informationB) 40.8 m C) 19.6 m D) None of the other choices is correct. Answer: B
Practice Test 1 1) Abby throws a ball straight up and times it. She sees that the ball goes by the top of a flagpole after 0.60 s and reaches the level of the top of the pole after a total elapsed time
More informationPhysics 111: Lecture 4: Chapter 4  Forces and Newton s Laws of Motion. Physics is about forces and how the world around us reacts to these forces.
Physics 111: Lecture 4: Chapter 4  Forces and Newton s Laws of Motion Physics is about forces and how the world around us reacts to these forces. Whats a force? Contact and noncontact forces. Whats a
More informationSection Review Answers. Chapter 12
Section Review Answers Chapter 12 Section 1 1. Answers may vary. Students should say in their own words that an object at rest remains at rest and an object in motion maintains its velocity unless it experiences
More informationPhysics 2A, Sec B00: Mechanics  Winter 2011 Instructor: B. Grinstein Final Exam
Physics 2A, Sec B00: Mechanics  Winter 2011 Instructor: B. Grinstein Final Exam INSTRUCTIONS: Use a pencil #2 to fill your scantron. Write your code number and bubble it in under "EXAM NUMBER;" an entry
More information1206EL  Concepts in Physics. Friday, September 18th
1206EL  Concepts in Physics Friday, September 18th Notes There is a WebCT course for students on September 21st More information on library webpage Newton s second law Newton's first law of motion predicts
More informationName: Date: PRACTICE QUESTIONS PHYSICS 201 FALL 2009 EXAM 2
Name: Date: PRACTICE QUESTIONS PHYSICS 201 FALL 2009 EXAM 2 1. A force accelerates a body of mass M. The same force applied to a second body produces three times the acceleration. What is the mass of the
More informationVersion 001 Quest 3 Forces tubman (20131) 1
Version 001 Quest 3 Forces tubman (20131) 1 This printout should have 19 questions. Multiplechoice questions may continue on the next column or page find all choices before answering. l B Conceptual
More informationF13HPhysQ5 Practice
Name: Class: Date: ID: A F13HPhysQ5 Practice Multiple Choice Identify the choice that best completes the statement or answers the question. 1. A vector is a quantity that has a. time and direction.
More informationFriction and Newton s 3rd law
Lecture 4 Friction and Newton s 3rd law Prereading: KJF 4.8 Frictional Forces Friction is a force exerted by a surface. The frictional force is always parallel to the surface Due to roughness of both
More informationA Review of Vector Addition
Motion and Forces in Two Dimensions Sec. 7.1 Forces in Two Dimensions 1. A Review of Vector Addition. Forces on an Inclined Plane 3. How to find an Equilibrant Vector 4. Projectile Motion Objectives Determine
More informationSpinning Stuff Review
Spinning Stuff Review 1. A wheel (radius = 0.20 m) is mounted on a frictionless, horizontal axis. A light cord wrapped around the wheel supports a 0.50kg object, as shown in the figure below. When released
More informationf max s = µ s N (5.1)
Chapter 5 Forces and Motion II 5.1 The Important Stuff 5.1.1 Friction Forces Forces which are known collectively as friction forces are all around us in daily life. In elementary physics we discuss the
More information3) a 1 = a 2. 5) a 1 = 2 a 2
ConcepTest Pulley Two masses are connected by a light rope as shown below. What is the 1) a 1 = 1/3 a 2 2) a 1 = ½ a 2 relationship between the magnitude of 3) a 1 = a 2 the acceleration of m 1 to that
More informationVectors and the Inclined Plane
Vectors and the Inclined Plane Introduction: This experiment is designed to familiarize you with the concept of force as a vector quantity. The inclined plane will be used to demonstrate how one force
More informationB) 286 m C) 325 m D) 367 m Answer: B
Practice Midterm 1 1) When a parachutist jumps from an airplane, he eventually reaches a constant speed, called the terminal velocity. This means that A) the acceleration is equal to g. B) the force of
More informationMULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) Vector A has length 4 units and directed to the north. Vector B has length 9 units and is directed
More informationMechanics 1. Revision Notes
Mechanics 1 Revision Notes July 2012 MECHANICS 1... 2 1. Mathematical Models in Mechanics... 2 Assumptions and approximations often used to simplify the mathematics involved:... 2 2. Vectors in Mechanics....
More informationUniversity Physics 226N/231N Old Dominion University. Newton s Laws and Forces Examples
University Physics 226N/231N Old Dominion University Newton s Laws and Forces Examples Dr. Todd Satogata (ODU/Jefferson Lab) satogata@jlab.org http://www.toddsatogata.net/2012odu Wednesday, September
More informationPH 2211D Spring Force and Motion II. Lecture Chapter 6 (Halliday/Resnick/Walker, Fundamentals of Physics 9 th edition)
PH 2211D Spring 2013 Force and Motion II Lecture 1213 Chapter 6 (Halliday/Resnick/Walker, Fundamentals of Physics 9 th edition) Chapter 6 Force and Motion II In this chapter we will cover the following
More informationB Answer: neither of these. Mass A is accelerating, so the net force on A must be nonzero Likewise for mass B.
CTA1. An Atwood's machine is a pulley with two masses connected by a string as shown. The mass of object A, m A, is twice the mass of object B, m B. The tension T in the string on the left, above mass
More information2. (b). The newton is a unit of weight, and the quantity (or mass) of gold that weighs 1 newton is m 1 N
QUICK QUIZZS 1. Newton s second law says that the acceleration of an object is directly proportional to the resultant (or net) force acting on. Recognizing this, consider the given statements one at a
More informationCh.4 Forces. Conceptual questions #1, 2, 12 Problem 1, 2, 5, 6, 7, 10, 12, 15, 16, 19, 20, 21, 23, 24, 26, 27, 30, 38, 39, 41, 42, 47, 50, 56, 66
Ch.4 Forces Conceptual questions #1, 2, 12 Problem 1, 2, 5, 6, 7, 10, 12, 15, 16, 19, 20, 21, 23, 24, 26, 27, 30, 38, 39, 41, 42, 47, 50, 56, 66 Forces Forces  vector quantity that changes the velocity
More informationForce. A force is a push or a pull. Pushing on a stalled car is an example. The force of friction between your feet and the ground is yet another.
Force A force is a push or a pull. Pushing on a stalled car is an example. The force of friction between your feet and the ground is yet another. Force Weight is the force of the earth's gravity exerted
More informationUNIT 2D. Laws of Motion
Name: Regents Physics Date: Mr. Morgante UNIT 2D Laws of Motion Laws of Motion Science of Describing Motion is Kinematics. Dynamics the study of forces that act on bodies in motion. First Law of Motion
More informationLecture 9. Friction in a viscous medium Drag Force Quantified
Lecture 9 Goals Describe Friction in Air (Ch. 6) Differentiate between Newton s 1 st, 2 nd and 3 rd Laws Use Newton s 3 rd Law in problem solving Assignment: HW4, (Chap. 6 & 7, due 10/5) 1 st Exam Thurs.,
More informationCOURSE CONTENT. Introduction. Definition of a Force Effect of Forces Measurement of forces. Newton s Laws of Motion
CHAPTER 13  FORCES COURSE CONTENT Introduction Newton s Laws of Motion Definition of a Force Effect of Forces Measurement of forces Examples of Forces A force is just a push or pull. Examples: an object
More information2. (P2.1 A) a) A car travels 150 km in 3 hours, what is the cars average speed?
Physics: Review for Final Exam 1 st Semester Name Hour P2.1A Calculate the average speed of an object using the change of position and elapsed time 1. (P2.1 A) What is your average speed if you run 140
More information6: Applications of Newton's Laws
6: Applications of Newton's Laws Friction opposes motion due to surfaces sticking together Kinetic Friction: surfaces are moving relative to each other a.k.a. Sliding Friction Static Friction: surfaces
More information