# UNIT-07. Newton s Three Laws of Motion

Save this PDF as:

Size: px
Start display at page:

Download "UNIT-07. Newton s Three Laws of Motion" ## Transcription

1 1. Learning Objectives: UNIT-07 Newton s Three Laws of Motion 1. Understand the three laws of motion, their proper areas of applicability and especially the difference between the statements of the first and the third laws 2. Know the difference between inertial and non-inertial frames of reference. 3. Be able to draw free-body diagrams for a single or a system of several objects. 4. Be able to use F = Ma (with item #3 above) to solve problems for a system of one or several objects. 5. Be familiar with concepts of static and kinetic friction. 6. Understand the concepts of tangential velocity and centripetal acceleration and be able to solve problems involving circular motion 2. Uniform Motion One of the central concepts in Newtonian dynamics is that of uniform motion. In Figure 1a-e are shown the positions of a particle at regular intervals of time. The motion of the particle can be described as follows: [a] [a] The velocity V = constant = 0, the particle is at rest. [b] The velocity V = Vi, where V is constant. [c] The speed is increasing, the direction remains unchanged. Thus, velocity is not constant and the particle has an acceleration. [b] X X [d] The speed is constant, the direction of motion is changing. Thus, velocity is not constant and the particle has an acceleration. [e] The speed and the direction of motion are changing. Thus, velocity is not constant and the particle has an acceleration. Points to note: [i] Motion with constant velocity implies motion in a straight line with constant speed. When a particle moves with constant velocity it is said to be in a state of uniform motion. Figure1a,b are examples of uniform motion. [e] [c] [d] X FIGURE 1

2 [ii] A particle not moving in a straight line is necessarily accelerating (Fig.1d,e). 3. Newton s Laws The first two laws are about change in the state of motion of a mass. The First Law: A mass will continue in a state of uniform motion unless an external agent exerts an influence on the mass. The Second Law: F = ma = m dv/dt  Comments: [a] The external agent mentioned in the first law is now identified as the force F. [b] If F = 0, then dv = 0,which implies uniform motion. Thus the statement of Newton s first law is contained in the second law. [c] F in eq. is the net force on m, F = F 1 + F 2 + F 3, where F 1, F 2, F 3, etc. are the individual forces acting on m. To emphasize this point, sometimes the second law (eq.) is written as: F = F 1 + " F 2 + " F = m " a  [d] Remember F = ma is a vector equation which means it expresses three relations: ΣFx = max ; ΣFy = may ; ΣFz = maz These equations imply that the acceleration of an object in a given direction is governed only by the net force in that direction. When ΣFx = ΣFy = ΣFz = 0, the system is said to be in equilibrium and the equation,

3 ΣFx = ΣFy = ΣFz = 0 is known as the first condition of equilibrium. [e] Newton had actually stated the second law as: F = dp/dt = d(mv)/dt = m dv/dt + Vdm/dt  Here p = mv is called the linear momentum. We will discuss the linear momentum in a few weeks. If the mass of the system doesn t change during motion, dm/dt = 0 and eq. reduces to eq.. 4. The Free-body Force Diagram. To apply F = ma to an object you must first find out the net force acting on it. This is done by drawing a free-body force diagram or simply free-body diagram (FBD) for the object. Review all the FBD examples discussed in the lectures. The Third Law The third law deals with interaction between two objects (call them 1 and 2) and states that the force exerted by 1 on 2 is equal in magnitude and opposite in direction to the force exerted by 2 on (BE CAREFUL :Every time you come across a pair of forces that are equal and opposite, don t confuse it with the action and reaction forces of the third Law.) Try the following. 1. You are pulling a crate by applying a force on it. The crate exerts an equal and opposite force on you. If these forces add up to zero according to the third Law then what makes the crate move? (Ans. The forces act on two different objects you and the crate and cannot be added to yield zero force. The motion of the crate is determined by the force, F,

4 acting on the crate. Since there is a net force exerted on it (by you), it moves according to F = ma. 2. A book of mass m is resting on the top of a table which in turn is resting on the floor (Fig.a). The FBD for the book is shown in Fig.(b) below. The force exerted by the Earth on the book, F be = mg is equal and opposite to the normal reaction force N exerted by the table on the book. Is the fact that F be N = 0 and therefore the book is in equilibrium an instance of Newton s third law or Newton s first Law? Answer: Both forces are acting on the same object. Therefore this is an instance of Newton s first Law (and the second Law), but not of the third Law. The reaction to F be is the force exerted by the book on the Earth F eb (see Fig.(c), it is NOT an FBD). The fact that F eb = - F be is an instance of the third Law. book book (a) table floor (earth) (b) F be N book (C) F be F eb EARTH

5 4.1 Using the FBD some examples. (We may not discuss this topic due to time constraints) Problem 1:A block of mass m = 50.0kg is released from rest on a frictionless inclined plane of angle What is the magnitude of the acceleration of the block? 37 0 Α 500sin37 ο =300N N A 37 ο 500cos37 o =400N 500N Step1. Draw the FBD for each part of the system. Make sure you label each force (or force component) and any angles involved. Remember you must draw all the forces acting ON the object of your interest. Do not include in the FBD any forces that the object exerts on other parts of the system or some external system. Improper or incomplete labeling can lead to an incorrect application of the second law. Step 2. Choose appropriate set of axes and decompose all forces along the two axes. In the example above we have chosen the x- axis along the incline pointing upward and the y- axis normal to the incline. Step- 3. Apply the first condition of equilibrium: ΣFx = max ; FBD. ΣFy = may to each In the present case we get the following equations for mass m: N 400 =  500sin37 o = 300 = 50a  Or a = 6.0m/s 2

6 Problem 2 : A block of mass m = 50.0kg on a frictionless inclined plane of angle 37 0 is connected by a cord over a massless and frictionless pulley to a second mass M= kg. [a] What is the magnitude of the acceleration of each block? [b] What is the tension T in the cord? (Note: In this problem we have simply attached another block B to the existing block A.. Notice how the FBD of block A and the resulting F = ma equation changes.) N T T A 37 o B 500sin37 ο =300N A B 37 ο 1000N 500cos37 o =400N 500N Step1. Draw the FBD for each part of the system. Make sure you label each force (or force component) and any angles involved. Remember you must draw all the forces acting ON the object of your interest. Do not include in the FBD any forces that the object exerts on other parts of the system or some external system. Improper or incomplete labeling can lead to an incorrect application of the second law. Step 2. Choose appropriate set of axes and decompose all forces along the two axes. In the example above we have chosen the x- axis along the incline pointing upward and the y- axis normal to the incline. Step- 3. Apply the first condition of equilibrium: ΣFx = max ; FBD. ΣFy = may to each

7 In the present case we get the following equations for mass m: N 400 =  T 300 = 50a  (Note: we are assuming the mass would move up the incline. If our assumption is right the value of a would turn out to be positive, if we made the wrong assumption the value of a would be negative. The negative value of a does not render our solution wrong. The physical interpretation would then tell us that the mass would be moving downward.) From the FBD of M, we get 1000 T = 100a  Step- 4. Solve the equations obtained in Step- 3. Thus we get, N = 400 N Adding  and  gives, 700 = 150a or a = 4.7m/s 2. From  T = a = N. Step- 5. SMILE 5. Concept Questions 1. Which of the following statements is most correct? (a) It is possible for an object to have motion in the absence of forces on the object. (b) It is possible to have forces on an object in the absence of motion of the object. (c) Neither (a) nor (b) is correct. (d) Both (a) and (b) are correct. Answer: (d). Choice (a) is true. Newton s first law tells us that motion requires no force: An object in motion continues to move at constant velocity in the absence of

8 external forces. Choice (b) is also true: A stationary object can have several forces acting on it, but if the vector sum of all these external forces is zero, there is no net force and the object remains stationary. 2. You push an object, initially at rest, across a frictionless floor with a constant force for a time interval t, resulting in a final speed of v for the object. You repeat the experiment, but with a force that is twice as large. What time interval is now required to reach the same final speed v? (a) 4 t (b) 2 t (c) t (d) t/2 (e) t/4 Answer: (d). With twice the force, the object will experience twice the acceleration. Because the force is constant, the acceleration is constant, and the speed of the object, starting from rest, is given by v = at. With twice the acceleration, the object will arrive at speed v at half the time. 3. If a fly collides with the windshield of a fast- moving bus, which experiences an impact force with a larger magnitude? (a) The fly does. (b) The bus does. (c) The same force is experienced by both. Which experiences the greater acceleration? (d) The fly does. (e) The bus does. (f) The same acceleration is experienced by both. Answer: (c), (d). In accordance with Newton s third law, the fly and the bus experience forces that are equal in magnitude but opposite in direction. Because the fly has such a small mass, Newton s second law tells us that it undergoes a very large acceleration. The huge mass of the bus means that it more effectively resists any change in its motion and exhibits a small acceleration. 4. Which of the following is the reaction force to the gravitational force acting on your body as you sit in your desk chair? (a) the normal force from the chair (b) the force you apply downward on the seat of the chair (c) neither of these forces Answer: (c). The reaction force to your weight is an upward gravitational force on the Earth caused by you.

9 PROBLEMS 1. A force F applied to an object of mass m1 produces an acceleration of 3.00 m/s 2. The same force applied to a second object of mass m2 produces an acceleration of 1.00 m/s 2. (a) What is the value of the ratio m1/m2? (b) If m1 and m2 are combined, find their acceleration under the action of the force F. For the same force F, acting on different masses F = m 1 a 1 and F = m 2 a 2 so m a = m a (a) m m 1 2 a2 = = a m = 3m 2 1 (b) F = ( m 1 + m 2 )a = 4m 1 a = m 1 ( 3.00 m s 2 ) a= m s 2 2. (a) A car with a mass of kg is moving to the right with a constant speed of 1.8 m/s. What is the total force on the car? (b) What is the total force on the car if it is moving to the left? Since the car is moving with constant speed and in a straight line, the resultant force on it must be zero regardless of whether it is moving (a) (b) toward the right or the left.

10 3. A kg object undergoes an acceleration given by a = (2.00î ĵ) m/s 2. Find the resultant force acting on it and the magnitude of the resultant force. m = 3.00 kg a = 2.00î ĵ ( ) m s 2 F = m a = 6.00î ĵ ( ) N F = 6.00 ( ) ( ) 2 N = 16.2 N 4. Two forces F 1 and F 2 act on a kg object. If F1 = 20.0 N and F2 = 15.0 N, find the accelerations in (a) and (b) of Figure 4. (a) F = F 1 + F 2 = ( 20.0î ĵ ) N or F = m a : 20.0î ĵ = 5.00 a a = 4.00î ĵ ( ) m s 2 F 2 F 2 F 1 (b) 2 a= m s at θ = F 2 x = 15.0cos60.0 = 7.50 N F 2 y = 15.0sin60.0 = 13.0 N F 2 = ( 7.50î ĵ ) N F = F 1 + F 2 = 27.5î ĵ a = 5.50î ĵ ( ) N = m a = 5.00 a ( ) m s 2 = 6.08 m s 2 at 25.3 F 1 FIG. 4a(top) and b

11 5. Three forces, given by F 1 = (2.00î ĵ) N, F 2 = (5.00î 3.00ĵ) N, and F 3 = (45.0î) N act on an object to give it an acceleration of magnitude 3.75 m/s2. (a) What is the direction of the acceleration? (b) What is the mass of the object? (c) If the object is initially at rest, what is its speed after 10.0 s? (d) What are the velocity components of the object after 10.0 s? F = m a reads (2.00î ĵ î 3.00ĵ 45.0î) N = m( 3.75 m s 2 )â where a represents the direction of a (42.0î 1.00ĵ ) N = m( 3.75 m s 2 )â F = ( 42.0) 2 + ( 1.00) N at tan 1 " \$ % # 42.0& ' below the x- axis F = 42.0 N at 181 = m 3.75 m s 2 ( )â. For the vectors to be equal, their magnitudes and their directions must be equal. (a) â is at 181 counterclockwise from the x-axis N (b) m= = kg m s (d) v f = v i + at = 0 + ( 3.75 m s 2 at 181 )10.0 s so v f = 37.5 m s at 181 v f = 37.5m s cos181 î m s sin181 ĵ so ( ) m s v f = 37.5î 0.893ĵ

12 (c) 2 2 v f = m s = m s 6. If a man weighs 900 N on the Earth, what would he weigh on Jupiter, where the free- fall acceleration is 25.9 m/s 2? F g = mg = 900 N, m = 900 N = 91.8 kg m s ( F g ) on Jupiter = 91.8 kg( 25.9 m s 2 ) = 2.38 kn 7. An electron of mass kg has an initial speed of m/s. It travels in a straight line, and its speed increases to m/s in a distance of 5.00 cm. Assuming that its acceleration is constant, (a) determine the net force exerted on the electron and (b) compare this force with the weight of the electron. v 2 2 f v (a) F = ma and v f = vi + 2ax f or a= 2x f Therefore, ( ) F = m v 2 2 f " v i 2x f F = 9.11# 10 "31 kg 2 i 2. \$ 7.00 # 10 5 %( m s 2 ) 2 " 3.00 # 10 5 m s m ( ) ( ) 2 & ' = 3.64 # 10 "18 N. (b) The weight of the electron is ( )( 9.80 m s 2 ) = "30 N F g = mg = "31 kg The accelerating force is times the weight of the electron.

### EQUATIONS OF MOTION: RECTANGULAR COORDINATES EQUATIONS OF MOTION: RECTANGULAR COORDINATES Today s Objectives: Students will be able to: 1. Apply Newton s second law to determine forces and accelerations for particles in rectilinear motion. In-Class

### Chapter 5. The Laws of Motion Chapter 5 The Laws of Motion The Laws of Motion The description of an object in motion included its position, velocity, and acceleration. There was no consideration of what might influence that motion.

### Forces and Newton s Laws Reading Notes. Give an example of a force you have experienced continuously all your life. Forces and Newton s Laws Reading Notes Name: Section 4-1: Force What is force? Give an example of a force you have experienced continuously all your life. Give an example of a situation where an object

### Chapter 3 The Laws of motion. The Laws of motion Chapter 3 The Laws of motion The Laws of motion The Concept of Force. Newton s First Law. Newton s Second Law. Newton s Third Law. Some Applications of Newton s Laws. 1 5.1 The Concept of Force Force:

### y(t) = y 0 t! 1 2 gt 2. With y(t final ) = 0, we can solve this for v 0 : v 0 A ĵ. With A! ĵ =!2 and A! = (2) 2 + (! 1. The angle between the vector! A = 3î! 2 ĵ! 5 ˆk and the positive y axis, in degrees, is closest to: A) 19 B) 71 C) 90 D) 109 E) 161 The dot product between the vector! A = 3î! 2 ĵ! 5 ˆk and the unit

### Phys101 Lecture 5 Dynamics: Newton s Laws of Motion Phys101 Lecture 5 Dynamics: Newton s Laws of Motion Key points: Newton s second law is a vector equation Action and reaction are acting on different objects Free-Body Diagrams Ref: 4-1,2,3,4,5,6,7. Page

### Physics 101 Lecture 5 Newton`s Laws Physics 101 Lecture 5 Newton`s Laws Dr. Ali ÖVGÜN EMU Physics Department The Laws of Motion q Newton s first law q Force q Mass q Newton s second law q Newton s third law qfrictional forces q Examples

### Newton s 3 Laws of Motion Newton s 3 Laws of Motion 1. If F = 0 No change in motion 2. = ma Change in motion Fnet 3. F = F 1 on 2 2 on 1 Newton s First Law (Law of Inertia) An object will remain at rest or in a constant state of

### Chapter 5 Newton s Laws of Motion. Copyright 2010 Pearson Education, Inc. 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

### Chapter 5. The Laws of Motion Chapter 5 The Laws of Motion The astronaut orbiting the Earth in the Figure is preparing to dock with a Westar VI satellite. The satellite is in a circular orbit 700 km above the Earth's surface, where

### Newton s Laws. Newton s Laws http://mathsforeurope.digibel.be/images Forces and Equilibrium If the net force on a body is zero, it is in equilibrium. dynamic equilibrium: moving relative to us static equilibrium: appears

### PHYSICS 221, FALL 2009 EXAM #1 SOLUTIONS WEDNESDAY, SEPTEMBER 30, 2009 PHYSICS 221, FALL 2009 EXAM #1 SOLUTIONS WEDNESDAY, SEPTEMBER 30, 2009 Note: The unit vectors in the +x, +y, and +z directions of a right-handed Cartesian coordinate system are î, ĵ, and ˆk, respectively.

### Chapter 6. Applications of Newton s Laws Chapter 6 Applications of Newton s Laws P. Lam 7_11_2018 Learning Goals for Chapter 5 Learn how to apply Newton s First Law & Second Law. Understand the cause of apparent weight and weightlessness Learn

### PHYS 101 Previous Exam Problems. Force & Motion I PHYS 101 Previous Exam Problems CHAPTER 5 Force & Motion I Newton s Laws Vertical motion Horizontal motion Mixed forces Contact forces Inclines General problems 1. A 5.0-kg block is lowered with a downward

### Chapter 4: Newton s Second Law F = m a. F = m a (4.2) Lecture 7: Newton s Laws and Their Applications 1 Chapter 4: Newton s Second Law F = m a First Law: The Law of Inertia An object at rest will remain at rest unless, until acted upon by an external force.

### Phys 1401: General Physics I 1. (0 Points) What course is this? a. PHYS 1401 b. PHYS 1402 c. PHYS 2425 d. PHYS 2426 2. (0 Points) Which exam is this? a. Exam 1 b. Exam 2 c. Final Exam 3. (0 Points) What version of the exam is this?

### PHYSICS - CLUTCH CH 04: INTRO TO FORCES (DYNAMICS) !! www.clutchprep.com FORCE, APPLIED FORCE, TENSION A force is either a push or a pull. Unit = ( ) - We ll represent all forces as a We ll refer to generic forces as forces. - Usually on an object by a

### CHAPTER 4 NEWTON S LAWS OF MOTION 62 CHAPTER 4 NEWTON S LAWS O MOTION CHAPTER 4 NEWTON S LAWS O MOTION 63 Up to now we have described the motion of particles using quantities like displacement, velocity and acceleration. These quantities

### Newton s Laws Pre-Test Newton s Laws Pre-Test 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)

### CEE 271: Applied Mechanics II, Dynamics Lecture 9: Ch.13, Sec.4-5 1 / 40 CEE 271: Applied Mechanics II, Dynamics Lecture 9: Ch.13, Sec.4-5 Prof. Albert S. Kim Civil and Environmental Engineering, University of Hawaii at Manoa 2 / 40 EQUATIONS OF MOTION:RECTANGULAR COORDINATES

### The Laws of Motion. Newton s first law Force Mass Newton s second law Gravitational Force Newton s third law Examples The Laws of Motion Newton s first law Force Mass Newton s second law Gravitational Force Newton s third law Examples Gravitational Force Gravitational force is a vector Expressed by Newton s Law of Universal

### REVISING MECHANICS (LIVE) 30 JUNE 2015 Exam Questions REVISING MECHANICS (LIVE) 30 JUNE 2015 Exam Questions Question 1 (Adapted from DBE November 2014, Question 2) Two blocks of masses 20 kg and 5 kg respectively are connected by a light inextensible string,

### Chapters 5-6. Dynamics: Forces and Newton s Laws of Motion. Applications Chapters 5-6 Dynamics: orces and Newton s Laws of Motion. Applications That is, describing why objects move orces Newton s 1 st Law Newton s 2 nd Law Newton s 3 rd Law Examples of orces: Weight, Normal,

### Physics 111. Help this week: Wednesday, 8-9 pm in NSC 118/119 Sunday, 6:30-8 pm in CCLIR 468. Response rate: 23 out of 33 ics day, ember 30, 2004 Mid-term survey results Ch 5: Newton s 3rd Law Ch 6: Examples Help this week: Wednesday, 8-9 pm in NSC 118/119 Sunday, 6:30-8 pm in CCLIR 468 Response rate: 23 out of 33 Several

### Physics B Newton s Laws AP Review Packet Force A force is a push or pull on an object. Forces cause an object to accelerate To speed up To slow down To change direction Unit: Newton (SI system) Newton s First Law The Law of Inertia. A body in

### variable Formula S or v SI variable Formula S or v SI 4. How is a Newton defined? What does a Newton equal in pounds? Newton s Laws 1 1. Define mass variable Formula S or v SI 2. Define inertia, how is inertia related to mass 3. What is a Force? variable Formula S or v SI 4. How is a Newton defined? What does a Newton

### Lecture 5. Dynamics. Forces: Newton s First and Second Lecture 5 Dynamics. Forces: Newton s First and Second What is a force? It s a pull or a push: F F Force is a quantitative description of the interaction between two physical bodies that causes them to

### Chapter 4. Dynamics: Newton s Laws of Motion. That is, describing why objects move Chapter 4 Dynamics: Newton s Laws of Motion That is, describing why objects move orces Newton s 1 st Law Newton s 2 nd Law Newton s 3 rd Law Examples of orces: Weight, Normal orce, Tension, riction ree-body

### Chap. 4: Newton s Law of Motion Chap. 4: Newton s Law of Motion And Chap.5 Applying Newton s Laws (more examples) Force; Newton s 3 Laws; Mass and Weight Free-body Diagram (1D) Free-body Diagram (1D, 2 Bodies) Free-body Diagram (2D)

### Welcome back to Physics 211 Welcome back to Physics 211 Today s agenda: Weight Friction Tension 07-1 1 Current assignments Thursday prelecture assignment. HW#7 due this Friday at 5 pm. 07-1 2 Summary To solve problems in mechanics,

### Phys 1401: General Physics I 1. (0 Points) What course is this? a. PHYS 1401 b. PHYS 1402 c. PHYS 2425 d. PHYS 2426 2. (0 Points) Which exam is this? a. Exam 1 b. Exam 2 c. Final Exam 3. (0 Points) What version of the exam is this?

### ME 230 Kinematics and Dynamics ME 230 Kinematics and Dynamics Wei-Chih Wang Department of Mechanical Engineering University of Washington Lecture 6: Particle Kinetics Kinetics of a particle (Chapter 13) - 13.4-13.6 Chapter 13: Objectives

### Lecture 7: More on Newton s Laws Lecture 7: More on Newton s Laws Other Important Aspects of the Second Law: Note that = ma is a vector equation, i.e., it is equivalent to saying: = ma x y z = ma = ma An object accelerates in the same

### Physics 2211 M Quiz #2 Solutions Summer 2017 Physics 2211 M Quiz #2 Solutions Summer 2017 I. (16 points) A block with mass m = 10.0 kg is on a plane inclined θ = 30.0 to the horizontal, as shown. A balloon is attached to the block to exert a constant

### Forces. Isaac Newton stated 3 laws that deal with forces and describe motion. Backbone of Physics FORCES Forces Isaac Newton stated 3 laws that deal with forces and describe motion. Backbone of Physics Inertia Tendency of an object to remain in the same state of motion. Resists a change in motion.

### Dynamics; Newton s Laws of Motion Dynamics; Newton s Laws of Motion Force A force is any kind of push or pull on an object. An object at rest needs a force to get it moving; a moving object needs a force to change its velocity. The magnitude

### Physics 111: Mechanics Lecture 5 Physics 111: Mechanics Lecture 5 Bin Chen NJIT Physics Department Forces of Friction: f q When an object is in motion on a surface or through a viscous medium, there will be a resistance to the motion.

### The Concept of Force Newton s First Law and Inertial Frames Mass Newton s Second Law The Gravitational Force and Weight Newton s Third Law Analysis The Laws of Motion The Concept of Force Newton s First Law and Inertial Frames Mass Newton s Second Law The Gravitational Force and Weight Newton s Third Law Analysis Models using Newton s Second Law Forces

### Chapter 5. Force and Motion I Chapter 5 Force and Motion I 5 Force and Motion I 25 October 2018 PHY101 Physics I Dr.Cem Özdoğan 2 3 5-2 Newtonian Mechanics A force is a push or pull acting on a object and causes acceleration. Mechanics

### Unit 1: Equilibrium and Center of Mass Unit 1: Equilibrium and Center of Mass FORCES What is a force? Forces are a result of the interaction between two objects. They push things, pull things, keep things together, pull things apart. It s really

### Reading Quiz. Chapter 5. Physics 111, Concordia College Reading Quiz Chapter 5 1. The coefficient of static friction is A. smaller than the coefficient of kinetic friction. B. equal to the coefficient of kinetic friction. C. larger than the coefficient of kinetic

### for any object. Note that we use letter, m g, meaning gravitational Lecture 4. orces, Newton's Second Law Last time we have started our discussion of Newtonian Mechanics and formulated Newton s laws. Today we shall closely look at the statement of the second law and consider

### Applying Newton s Laws Chapter 5 Applying Newton s Laws PowerPoint Lectures for University Physics, Twelfth Edition Hugh D. Young and Roger A. Freedman Lectures by James Pazun Goals for Chapter 5 To use and apply Newton s Laws

### Physics 8 Wednesday, October 19, Troublesome questions for HW4 (5 or more people got 0 or 1 points on them): 1, 14, 15, 16, 17, 18, 19. Yikes! Physics 8 Wednesday, October 19, 2011 Troublesome questions for HW4 (5 or more people got 0 or 1 points on them): 1, 14, 15, 16, 17, 18, 19. Yikes! Troublesome HW4 questions 1. Two objects of inertias

### Chapter 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

### Physics for Scientists and Engineers. Chapter 6 Dynamics I: Motion Along a Line Physics for Scientists and Engineers Chapter 6 Dynamics I: Motion Along a Line Spring, 008 Ho Jung Paik Applications of Newton s Law Objects can be modeled as particles Masses of strings or ropes are negligible

### PHYS-2010: General Physics I Course Lecture Notes Section V PHYS-2010: General Physics I Course Lecture Notes Section V Dr. Donald G. Luttermoser East Tennessee State University Edition 2.5 Abstract These class notes are designed for use of the instructor and students

### Chapter 5. Force and Motion-I Chapter 5 Force and Motion-I 5.3 Newton s First Law Newton s First Law: If no force acts on a body, the body s velocity cannot change The purpose of Newton s First Law is to introduce the special frames

### Q2. A book whose mass is 2 kg rests on a table. Find the magnitude of the force exerted by the table on the book. AP Physics 1- Dynamics Practice Problems FACT: Inertia is the tendency of an object to resist a change in state of motion. A change in state of motion means a change in an object s velocity, therefore

### PHYSICS 221 SPRING EXAM 1: February 20, 2014; 8:15pm 10:15pm PHYSICS 221 SPRING 2014 EXAM 1: February 20, 2014; 8:15pm 10:15pm Name (printed): Recitation Instructor: Section # INSTRUCTIONS: This exam contains 25 multiple-choice questions plus 2 extra credit questions,

### Forces and Newton s Laws Notes Forces and Newton s Laws Notes Force An action exerted on an object which can change the motion of the object. The SI unit for force is the Newton (N) o N = (kg m)/s 2 o Pound is also a measure of force

### Prof. Dr. I. Nasser T171 Chapter5_I 12/10/2017 Prof. Dr. I. Nasser T171 Chapter5_I 1/10/017 Chapter 5 Force and Motion I 5-1 NEWTON S FIRST AND SECOND LAWS Newton s Three Laws Newton s 3 laws define some of the most fundamental things in physics including:

### Chapter 4 Dynamics: Newton s Laws of Motion Chapter 4 Dynamics: Newton s Laws of Motion 4-1 Force A force is a push or pull. An object at rest needs a force to get it moving; a moving object needs a force to change its velocity. The magnitude of

### (35+70) 35 g (m 1+m 2)a=m1g a = 35 a= =3.27 g 105 Coordinator: Dr. W. L-Basheer Monday, March 16, 2015 Page: 1 Q1. 70 N block and a 35 N block are connected by a massless inextendable string which is wrapped over a frictionless pulley as shown in Figure

### AP Physics I Summer Work AP Physics I Summer Work 2018 (20 points) Please complete the following set of questions and word problems. Answers will be reviewed in depth during the first week of class followed by an assessment based

### Applying Newton s Laws Chapter 5 Applying Newton s Laws PowerPoint Lectures for University Physics, Twelfth Edition Hugh D. Young and Roger A. Freedman Lectures by James Pazun Copyright 2008 Pearson Education Inc., publishing

### Chapter 5. The Laws of Motion Chapter 5 The Laws of Motion Sir Isaac Newton 1642 1727 Formulated basic laws of mechanics Discovered Law of Universal Gravitation Invented form of calculus Many observations dealing with light and optics

### Unit 5 Forces I- Newton s First & Second Law Unit 5 Forces I- Newton s First & Second Law Unit is the NEWTON(N) Is by definition a push or a pull Does force need a Physical contact? Can exist during physical contact(tension, Friction, Applied Force)

### Main points of today s lecture: Normal force Newton s 3 d Law Frictional forces: kinetic friction: static friction Examples. Physic 231 Lecture 9 Main points of today s lecture: Normal force Newton s 3 d Law Frictional forces: kinetic friction: static friction Examples. Physic 3 Lecture 9 f N k = µ k f N s < µ s Atwood s machine Consider the Atwood

### Physics 111 Lecture 4 Newton`s Laws Physics 111 Lecture 4 Newton`s Laws Dr. Ali ÖVGÜN EMU Physics Department www.aovgun.com he Laws of Motion q Newton s first law q Force q Mass q Newton s second law q Newton s third law q Examples Isaac

### MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. Diagram 1 A) B - A. B) A - B. C) A + B. D) A B. Exam Name MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) In the diagram shown, the unknown vector is 1) Diagram 1 A) B - A. B) A - B. C) A + B.

### Physics 201 Lecture 16 Physics 01 Lecture 16 Agenda: l Review for exam Lecture 16 Newton s Laws Three blocks are connected on the table as shown. The table has a coefficient of kinetic friction of 0.350, the masses are m 1 =

### Forces Part 1: Newton s Laws Forces Part 1: Newton s Laws Last modified: 13/12/2017 Forces Introduction Inertia & Newton s First Law Mass & Momentum Change in Momentum & Force Newton s Second Law Example 1 Newton s Third Law Common

### Physics 201, Review 2 Physics 201, Review 2 Important Notes: v This review does not replace your own preparation efforts v The review is not meant to be complete. v Exercises used in this review do not form a test problem pool.

### CHAPTER 4 TEST REVIEW -- Answer Key AP PHYSICS Name: Period: Date: DEVIL PHYSICS BADDEST CLASS ON CAMPUS 50 Multiple Choice 45 Single Response 5 Multi-Response Free Response 3 Short Free Response 2 Long Free Response AP EXAM CHAPTER TEST

### Newton s First Law and IRFs Goals: Physics 207, Lecture 6, Sept. 22 Recognize different types of forces and know how they act on an object in a particle representation Identify forces and draw a Free Body Diagram Solve 1D and 2D

### Newton s 3 rd Law. Book page 48-49 Newton s 3 rd Law Book page 48-49 14/9/2016 cgrahamphysics.com 2016 Newton s 2 nd Law problem Newton s second law does not always work: - does not work when applied to atoms and molecules - does not work

### A. B. C. D. E. v x. ΣF x Q4.3 The graph to the right shows the velocity of an object as a function of time. Which of the graphs below best shows the net force versus time for this object? 0 v x t ΣF x ΣF x ΣF x ΣF x ΣF x 0 t 0

### Isaac Newton ( ) 1687 Published Principia Invented Calculus 3 Laws of Motion Universal Law of Gravity Isaac Newton (1642-1727) 1687 Published Principia Invented Calculus 3 Laws of Motion Universal Law of Gravity Newton s First Law (Law of Inertia) An object will remain at rest or in a constant state of

### Webreview practice test. Forces (again) Please do not write on test. ID A Webreview 4.3 - practice test. Forces (again) Multiple Choice Identify the choice that best completes the statement or answers the question. 1. A 5.0-kg mass is suspended

### 1. Draw a FBD of the toy plane if it is suspended from a string while you hold the string and move across the room at a constant velocity. 1. Draw a FBD of the toy plane if it is suspended from a string while you hold the string and move across the room at a constant velocity. 2. A 15 kg bag of bananas hangs from a taunt line strung between

### Sara Rwentambo. PHYS 1007 AB Topics: Free body diagrams (FBDs) Static friction and kinetic friction Tension and acceleration of a system Tension in dynamic equilibrium (bonus question) Opener: Find Your Free Body Diagram Group Activity!

### Physics 207 Lecture 7. Lecture 7 Lecture 7 "Professor Goddard does not know the relation between action and reaction and the need to have something better than a vacuum against which to react. He seems to lack the basic knowledge ladled

### Discussion Session 6 Newton s Second & Third Laws Week 07. The Plan PHYS 100 Discussion Session 6 Newton s Second & Third Laws Week 07 The Plan This week we use Newton s Third Law ( F A on B = F B on A ) to relate the forces between two different objects. We can use this

### Chapter 5 Newton s Laws of Motion Chapter 5 Newton s Laws of Motion Newtonian Mechanics Mass Mass is an intrinsic characteristic of a body The mass of a body is the characteristic that relates a force on the body to the resulting acceleration.

### PSI AP Physics B Dynamics PSI AP Physics B Dynamics Multiple-Choice questions 1. After firing a cannon ball, the cannon moves in the opposite direction from the ball. This an example of: A. Newton s First Law B. Newton s Second

### Bell Ringer: What is Newton s 3 rd Law? Which force acts downward? Which force acts upward when two bodies are in contact? Bell Ringer: What is Newton s 3 rd Law? Which force acts downward? Which force acts upward when two bodies are in contact? Does the moon attract the Earth with the same force that the Earth attracts the

### Newton s Laws and Free-Body Diagrams General Physics I Newton s Laws and Free-Body Diagrams In the next few sections, we will be exploring some of the most fundamental laws of our universe, laws that govern the relationship actions and motion. These laws are

### Question 01. A. Incorrect! This is not Newton s second law. College Physics - Problem Drill 06: Newton s Laws of Motion Question No. 1 of 10 1. Which of the options best describes the statement: Every object continues in a state of rest or uniform motion in a straight

### Chapter 5 Gravitation Chapter 6 Work and Energy Chapter 5 Gravitation Chapter 6 Work and Energy Chapter 5 (5.6) Newton s Law of Universal Gravitation (5.7) Gravity Near the Earth s Surface Chapter 6 (today) Work Done by a Constant Force Kinetic Energy,

### Physics 8 Monday, October 9, 2017 Physics 8 Monday, October 9, 2017 Pick up a HW #5 handout if you didn t already get one on Wednesday. It s due this Friday, 10/13. It contains some Ch9 (work) problems, some Ch10 (motion in a plane) problems,

### Physics 185F2013 Lecture Two Introduction Physics 185F2013 Lecture Two October 1, 2013 Dr. Jones 1 1 Department of Physics Drexel University October 1, 2013 Dr. Jones (Drexel) Physics 185F2013 Lecture Two October 1, 2013 1 / 39 Introduction

### WS-CH-4 Motion and Force Show all your work and equations used. Isaac Newton ( ) AP PHYSICS 1 WS-CH-4 Motion and Force Show all your work and equations used. Isaac Newton (1643-1727) Isaac Newton was the greatest English mathematician of his generation. He laid the foundation for differential

### Review: Advanced Applications of Newton's Laws Review: Advanced Applications of Newton's Laws 1. The free-body diagram of a wagon being pulled along a horizontal surface is best represented by a. A d. D b. B e. E c. C 2. The free-body diagram of a

### You may use g = 10 m/s 2, sin 60 = 0.87, and cos 60 = 0.50. 1. A child pulls a 15kg sled containing a 5kg dog along a straight path on a horizontal surface. He exerts a force of a 55N on the sled at an angle of 20º above the horizontal. The coefficient of friction

### Welcome to Forces an anticipation guide A force is defined as a push or a pull When answering the following true or false statements, offer a Welcome to Forces an anticipation guide A force is defined as a push or a pull When answering the following true or false statements, offer a real-life example that justifies your answer. You haven t answered

### Chapter 6. Circular Motion and Other Applications of Newton s Laws Chapter 6 Circular Motion and Other Applications of Newton s Laws Circular Motion Two analysis models using Newton s Laws of Motion have been developed. The models have been applied to linear motion. Newton

### Physics 101. Hour Exam I Fall Last Name: First Name Network-ID Discussion Section: Discussion TA Name: Last Name: First Name Network-ID Discussion Section: Discussion TA Name: Instructions Turn off your cell phone and put it away. This is a closed book exam. You have ninety (90) minutes to complete it.

### Name: Class: Date: so sliding friction is better so sliding friction is better d. µ k Name: Class: Date: Exam 2--PHYS 101-F08 Multiple Choice Identify the choice that best completes the statement or answers the question. 1. You put your book on the seat next to you. When the bus stops,

### Concept of Force and Newton s Laws of Motion Concept of Force and Newton s Laws of Motion 8.01 W02D2 Chapter 7 Newton s Laws of Motion, Sections 7.1-7.4 Chapter 8 Applications of Newton s Second Law, Sections 8.1-8.4.1 Announcements W02D3 Reading

### Chapter 6 Dynamics I: Motion Along a Line Chapter 6 Dynamics I: Motion Along a Line Chapter Goal: To learn how to solve linear force-and-motion problems. Slide 6-2 Chapter 6 Preview Slide 6-3 Chapter 6 Preview Slide 6-4 Chapter 6 Preview Slide

### Practice. Newton s 3 Laws of Motion. Recall. Forces a push or pull acting on an object; a vector quantity measured in Newtons (kg m/s²) Practice A car starts from rest and travels upwards along a straight road inclined at an angle of 5 from the horizontal. The length of the road is 450 m and the mass of the car is 800 kg. The speed of

### Chapter 8: Dynamics in a plane 8.1 Dynamics in 2 Dimensions p. 210-212 Chapter 8: Dynamics in a plane 8.2 Velocity and Acceleration in uniform circular motion (a review of sec. 4.6) p. 212-214 8.3 Dynamics of Uniform Circular Motion

### AP Mechanics Summer Assignment 2012-2013 AP Mechanics Summer Assignment To be completed in summer Submit for grade in September Name: Date: Equations: Kinematics (For #1 and #2 questions: use following equations only. Need to show derivation

### Physics 1 Second Midterm Exam (AM) 2/25/2010 Physics Second Midterm Eam (AM) /5/00. (This problem is worth 40 points.) A roller coaster car of m travels around a vertical loop of radius R. There is no friction and no air resistance. At the top of

### AP Physics C: Work, Energy, and Power Practice AP Physics C: Work, Energy, and Power Practice 1981M2. A swing seat of mass M is connected to a fixed point P by a massless cord of length L. A child also of mass M sits on the seat and begins to swing 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 Chapter 6: FORCE AND MOTION II 1 A brick slides on a horizontal surface Which of the following will increase the magnitude of the frictional force on it? A Putting a second brick on top B Decreasing the