# PHYSICS 111 HOMEWORK SOLUTION, week 4, chapter 5, sec 1-7. February 13, 2013

Save this PDF as:

Size: px
Start display at page:

Download "PHYSICS 111 HOMEWORK SOLUTION, week 4, chapter 5, sec 1-7. February 13, 2013"

## Transcription

1 PHYSICS 111 HOMEWORK SOLUTION, week 4, chapter 5, sec 1-7 February 13, 2013

2 0.1 A 2.00-kg object undergoes an acceleration given by a = (6.00î ĵ)m/s 2 a) Find the resultatnt force acting on the object b) Find the magnitude of the resultant force a) Newton s Second Law: F = m a with m = 2.00kg and a = (6.00î ĵ)m/s 2 F = 2.00 (6.00î ĵ) F = (12.00î ĵ)N b) Magnitude of the resultant force F = F = 208 F = 14.42N 2

3 The average speed of a nitrogen molecule in air is about m/s, and its mass is about kg a) If it takes s for a nitrogen molecule to hit a wall and rebound with the same speed but moving in an opposite direction (assumed to be the negative direction), what is the average acceleration of the molecule during this time interval? b) What average force does the molecule exert on the wall? a) Average acceleration of the molecule: Velocity vector is changing sign but keep a constant magnitude: v before = vî and v after = vî the change in velocity is: v = vî vî = 2vî the change in magnitude is just : v = 2v, with average acceleration of : b) Average force exerted : a = v t = 2v t = = m/s 2 Newton s Second Law : F = m a, with magnitude F = ma = = N 3

4 0.3 Two forces F 1 and F 2 act on a 4.80-kg object. F 1 = 30.0N and F 2 = 16.0N. a) Find the acceleration of the object for the configuration of forces shown in Figure (a). b) Find the acceleration of the object for the configuration of forces shown in Figure (b). a) Acceleration magnitude and direction (from the horizontal x-axis) Newton s Second Law: F = m a F 1 = 30î and F 2 = 16ĵ resulting in F = 30î + 16ĵ Magnitude : and direction angle: a = F m = 30î + 16ĵ 4.80 = 6.25î ĵ a = = 7.08m/s 2 θ = arctan ( ) = 28 4

5 0.3. b) F 1 = 30î But F 2 = F 2 [cos 60 î + sin 60 ĵ] = 16(0.5î ĵ) = 8î ĵ a = F m = 38î ĵ 4.80 = 7.91î ĵ Magnitude : a = = 8.42m/s 2 and direction angle: θ = arctan ( ) = 20 5

6 0.4 A 17.0-lb block rests on the floor. a) What force does the floor exert on the block? b) If a rope is tied to the block and run vertically over a pulley, and the other end is attached to a free-hanging 10.5-lb weight, what is the force exerted by the floor on the 17.0-lb block? If we replace the 10.5-lb weight in part (b) with a 36.0-lb weight, what is the force exerted by the floor on the 17.0-lb block? a) 1-lb = kg The block is at rest on the horizontal floor, gravity force F g (pointing downward) is balanced by a normal force (pointing upward) F n exerted by the floor to keep the block at rest, the two are equal in magnitude: F n = F g = mg = Its direction is : upward F n = 75.6N b) The rope tied to the block vertically will generate a force T pointing upward and equal in magnitude to the gravity force acting on the free-hanging block: T = m g = = 46.7N The forces acting on the block in this situation are : 6

7 0.5. F g = 75.6ĵ T = 46.7ĵ F n pointing downward pointing upward pointing upward Forces should balance eachother to keep the block in rest: Fn + T = F g F n = T F g = 46.7ĵ ĵ = 28.9ĵ magnitude is : 28.9 N direction is : upward c) The new free hanging weight is heavier than the block (36-lb vs 17-lb), the block will be lifted up from the floor and there will be no contact. The force exerted by the floor will not exist. Remember that forces of this type are contact forces unlike gravity. 0.5 The distance between two telephone poles is d = 48.5 m. When a kg bird lands on the telephone wire midway between the poles, the wire sags h = m. a)draw a free-body diagram of the bird. (Do this on paper. Your instructor may ask you to turn in this diagram.) b) How much tension does the bird produce in the wire? Ignore the weight of the wire. 7

8 a) The free body diagram of the bird d=48.5m T 2 T1 α h d/2 Free Body Diagram F g = m g b) The tension produced by the bird in the wire is the same tension produced by the wire on the bird (action-reaction law). For symetry considerations T 1 and T 2 are of same magnitude. Newtons Law : F = Fg + T 1 + T 2 = 0 A projection on the vertical axis should give: T 1 sin α + T 2 sin α mg = 0 with T 1 = T 2 = T on the other hand tan α = h d/2 = = thus α = 0.47 T = mg 2 sin α = sin 0.47 = 568N 8

9 An object of mass m 1 = 3.80-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 = 7.20-kg as shown in the figure. a) Draw free-body diagrams of both objects. b)find the magnitude of the acceleration of the objects. ) Find the tension in the string. a) Free body diagrams Object +y F N T T +x m 1 g m 2 g + b) For object m 1 F = m1 g + T + F N = m 1 a 1 ; Prejection on the x-axis should give: 0 + T + 0 = m 1 a 1 (1) a 1 = a 1 î (horizontal motion) 9

10 For object m 2 F = m2 g + T = m 2 a 2 ; a 2 = a 2 ĵ (vertical motion) Prejection on the y-axis (+ sign downward only for convenience)should give: m 2 g T = m 2 a 2 (2) the two objects are connected together and the magnitude of their accelerations is the same: a 1 = a 2 = a the string tensions are also the same T = T We can derive : m 1 a = T = m 2 g m 2 a and finally a = m 2 g m 1 + m 2 = = 6.42m/s 2 c) Tension in the strings T = m 1 a = = 24.4N 10

11 In the Atwood machine shown below, m 1 = 2.00-kg and m 2 = 5.60-kg. The masses of the pulley and string are negligible by comparison. The pulley turns without friction and the string does not stretch. The lighter object is released with a sharp push that sets it into motion at v i = 2.15 m/s downward. a) How far will m 1 descend below its initial level? b) Find the velocity of m 1 after 1.80 s. a) We can start by drawing the body diagrams for both masses with the directions of choice: +y T T m 1 g m 2 g + m 1 descending m 1 g + T = m 1 a 11

12 m 2 ascending m 2 g T = m 2 a this gives : (m 2 m 1 )g = (m 1 + m 2 )a and a = (m 2 m 1 )g m 1 + m 2 = = 4.65m/s 2 ( ) we can use the time-independent equation to derive the distance crossed by mass m 1 at the moment its velocity vanishes and about to start rising v 2 f v 2 i = 2ad then d = v2 f v2 i 2a = (4.65) = 0.497m d = 49.7cm b) to get the velocity of m 1 we use : v = v i + at = t at t = 1.80s the velocity is v = = 6.22m/s its direction is upward 12

13 Three blocks are in contact with one another on a frictionless, horizontal surface as shown in the figure below. A horizontal force is applied to m 1. Take m 1 = 2.00kg, m 2 = 3.00 kg, m 3 = 4.55 kg, and F = 22.5 N. a) Draw a separate free-body diagram for each block. b) Find the acceleration of the blocks c) Find the resultant force on each block. d) Find the magnitudes of the contact forces between the blocks. e) You are working on a construction project. A coworker is nailing up plasterboard on one side of a light partition, and you are on the opposite side, providing backing by leaning against the wall with your back pushing on it. Every hammer blow makes your back sting. The supervisor helps you put a heavy block of wood between the wall and your back. Using the situation analyzed in parts (a) through (d) as a model, explain how this change works to make your job more comfortable. 13

14 a) The free Body diagrams We use the following notations: F i/j for the force exxerted by mass i on mass j. F in for the normal force exerted by the surface on mass i (no friction) mass m 1 +y F 1N F 2/1 F +x m 1 g mass m 2 +y F 2N F 3/2 F1/2 +x m 2 g mass m 3 +y F 3N F 2/3 +x m 3 g b) acceleration of the blocks all the block will be moving with the same acceleration and velocit. F = m1 a projected on the x-axis 14

15 0.8. on each mass we get the set of the following equations: F 2/3 = m 3 a F 1/2 F 3/2 = m 2 a F F 2/1 = m 1 a action/reaction principle requires F 1/2 = F 2/1 and F 2/3 = F 3/2 m 3 a = F 1/2 m 2 a = F m 1 a m 2 a ; (m 1 + m 2 + m 3 )a = F a = F m 1 + m 2 + m 3 = = 2.36m/s 2 The acceleration has the direction : Left Right c) Resultant force on each block Fi = m i a on m 1 F1 = m 1 a = = 4.72N on m 2 F2 = m 2 a = = 7.08N on m 3 F3 = m 3 a = = 10.74N d)magnitudes of the contact forces From the equations of section b) d) F 2/1 = F 1/2 = F m 1 a = = 17.8N F 3/2 = F 2/3 = F 1/2 m 2 a = = 10.7N Notice that the horizontal forces are reducing in magnitude going from block to block towards the right side: F > F 1/2 > F 2/3 The impact of the nailing will be less and less as we put more blocks. By stacking plasterboard blocks we can make a coworker s job much more comfortable. 15

### v 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

### Newton 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

### 04-1. 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

### 5. Forces and Motion-I. Force is an interaction that causes the acceleration of a body. A vector quantity.

5. Forces and Motion-I 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

### 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

### PHYS101 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

### This 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

### PHYSICS 111 HOMEWORK#6 SOLUTION. February 22, 2013

PHYSICS 111 HOMEWORK#6 SOLUTION February 22, 2013 0.1 A block of mass m = 3.20 kg is pushed a distance d = 4.60 m along a frictionless, horizontal table by a constant applied force of magnitude F = 16.0

### Physics: 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 buckle-up? A) the first law

### B) 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

### Two-Body System: Two Hanging Masses

Specific Outcome: i. I can apply Newton s laws of motion to solve, algebraically, linear motion problems in horizontal, vertical and inclined planes near the surface of Earth, ignoring air resistance.

### Mechanics 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....

### Newton 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

### Acceleration due to Gravity

Acceleration due to Gravity 1 Object To determine the acceleration due to gravity by different methods. 2 Apparatus Balance, ball bearing, clamps, electric timers, meter stick, paper strips, precision

### Ground 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

### Objective: Equilibrium Applications of Newton s Laws of Motion I

Type: Single Date: Objective: Equilibrium Applications of Newton s Laws of Motion I Homework: Assignment (1-11) Read (4.1-4.5, 4.8, 4.11); Do PROB # s (46, 47, 52, 58) Ch. 4 AP Physics B Mr. Mirro Equilibrium,

### Newton 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

### MOTION AND FORCE: DYNAMICS

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

### C B A T 3 T 2 T 1. 1. What is the magnitude of the force T 1? A) 37.5 N B) 75.0 N C) 113 N D) 157 N E) 192 N

Three boxes are connected by massless strings and are resting on a frictionless table. Each box has a mass of 15 kg, and the tension T 1 in the right string is accelerating the boxes to the right at a

### Physics-1 Recitation-3

Physics-1 Recitation-3 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

### 1. 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

### Chapter 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

### Rotational Mechanics - 1

Rotational Mechanics - 1 The Radian The radian is a unit of angular measure. The radian can be defined as the arc length s along a circle divided by the radius r. s r Comparing degrees and radians 360

### 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

### Chapter 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?

### Lecture 6. Weight. Tension. Normal Force. Static Friction. Cutnell+Johnson: 4.8-4.12, second half of section 4.7

Lecture 6 Weight Tension Normal Force Static Friction Cutnell+Johnson: 4.8-4.12, second half of section 4.7 In this lecture, I m going to discuss four different kinds of forces: weight, tension, the normal

### 1 of 7 10/2/2009 1:13 PM

1 of 7 10/2/2009 1:13 PM Chapter 6 Homework Due: 9:00am on Monday, September 28, 2009 Note: To understand how points are awarded, read your instructor's Grading Policy. [Return to Standard Assignment View]

### W02D2-2 Table Problem Newton s Laws of Motion: Solution

ASSACHUSETTS INSTITUTE OF TECHNOLOGY Department of Physics Physics 8.01 W0D- Table Problem Newton s Laws of otion: Solution Consider two blocks that are resting one on top of the other. The lower block

### A Determination of g, the Acceleration Due to Gravity, from Newton's Laws of Motion

A Determination of g, the Acceleration Due to Gravity, from Newton's Laws of Motion Objective In the experiment you will determine the cart acceleration, a, and the friction force, f, experimentally for

### Example (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

### Physics 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

### AP 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

### Chapter 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?!

### TEACHER ANSWER KEY November 12, 2003. Phys - Vectors 11-13-2003

Phys - Vectors 11-13-2003 TEACHER ANSWER KEY November 12, 2003 5 1. A 1.5-kilogram lab cart is accelerated uniformly from rest to a speed of 2.0 meters per second in 0.50 second. What is the magnitude

### FRICTION, WORK, AND THE INCLINED PLANE

FRICTION, WORK, AND THE INCLINED PLANE Objective: To measure the coefficient of static and inetic friction between a bloc and an inclined plane and to examine the relationship between the plane s angle

### Homework 4. problems: 5.61, 5.67, 6.63, 13.21

Homework 4 problems: 5.6, 5.67, 6.6,. Problem 5.6 An object of mass M is held in place by an applied force F. and a pulley system as shown in the figure. he pulleys are massless and frictionless. Find

### LAB 6 - GRAVITATIONAL AND PASSIVE FORCES

L06-1 Name Date Partners LAB 6 - GRAVITATIONAL AND PASSIVE FORCES OBJECTIVES And thus Nature will be very conformable to herself and very simple, performing all the great Motions of the heavenly Bodies

### SOLUTIONS TO PROBLEM SET 4

MASSACHUSETTS INSTITUTE OF TECHNOLOGY Department of Physics Physics 8.01X Fall Term 2002 SOLUTIONS TO PROBLEM SET 4 1 Young & Friedman 5 26 A box of bananas weighing 40.0 N rests on a horizontal surface.

### Physics 2101, First Exam, Fall 2007

Physics 2101, First Exam, Fall 2007 September 4, 2007 Please turn OFF your cell phone and MP3 player! Write down your name and section number in the scantron form. Make sure to mark your answers in the

### Physics 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

### LAB 6: GRAVITATIONAL AND PASSIVE FORCES

55 Name Date Partners LAB 6: GRAVITATIONAL AND PASSIVE FORCES And thus Nature will be very conformable to herself and very simple, performing all the great Motions of the heavenly Bodies by the attraction

### 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)

### physics 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

### A) N > W B) N = W C) N < W. speed v. Answer: N = W

CTN-12. 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

### Version 001 Quest 3 Forces tubman (20131) 1

Version 001 Quest 3 Forces tubman (20131) 1 This print-out should have 19 questions. Multiple-choice questions may continue on the next column or page find all choices before answering. l B Conceptual

### Recitation Week 4 Chapter 5

Recitation Week 4 Chapter 5 Problem 5.5. A bag of cement whose weight is hangs in equilibrium from three wires shown in igure P5.4. wo of the wires make angles θ = 60.0 and θ = 40.0 with the horizontal.

### Lecture 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.,

### Explaining 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

### HW#4b Page 1 of 6. I ll use m = 100 kg, for parts b-c: 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

### Newton s Second Law. ΣF = m a. (1) In this equation, ΣF is the sum of the forces acting on an object, m is the mass of

Newton s Second Law Objective The Newton s Second Law experiment provides the student a hands on demonstration of forces in motion. A formulated analysis of forces acting on a dynamics cart will be developed

### Chapter 18 Static Equilibrium

Chapter 8 Static Equilibrium 8. Introduction Static Equilibrium... 8. Lever Law... Example 8. Lever Law... 4 8.3 Generalized Lever Law... 5 8.4 Worked Examples... 7 Example 8. Suspended Rod... 7 Example

### General Physics Lab: Atwood s Machine

General Physics Lab: Atwood s Machine Introduction One may study Newton s second law using a device known as Atwood s machine, shown below. It consists of a pulley and two hanging masses. The difference

### Chapter 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 well-defined rules. The book Philosophiae

### Chapter 4. Forces and Newton s Laws of Motion. continued

Chapter 4 Forces and Newton s Laws of Motion continued Clicker Question 4.3 A mass at rest on a ramp. How does the friction between the mass and the table know how much force will EXACTLY balance the gravity

### A 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

### Mass, energy, power and time are scalar quantities which do not have direction.

Dynamics Worksheet Answers (a) Answers: A vector quantity has direction while a scalar quantity does not have direction. Answers: (D) Velocity, weight and friction are vector quantities. Note: weight and

### Physics 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

### Solution Derivations for Capa #11

Solution Derivations for Capa #11 1) A horizontal circular platform (M = 128.1 kg, r = 3.11 m) rotates about a frictionless vertical axle. A student (m = 68.3 kg) walks slowly from the rim of the platform

### www.mathsbox.org.uk Displacement (x) Velocity (v) Acceleration (a) x = f(t) differentiate v = dx Acceleration Velocity (v) Displacement x

Mechanics 2 : Revision Notes 1. Kinematics and variable acceleration Displacement (x) Velocity (v) Acceleration (a) x = f(t) differentiate v = dx differentiate a = dv = d2 x dt dt dt 2 Acceleration Velocity

### B Answer: neither of these. Mass A is accelerating, so the net force on A must be non-zero Likewise for mass B.

CTA-1. 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

### AP1 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 action-reaction force pairs in this interchange. (A) foot applies 200 newton force to nose; nose applies

### Lecture Outline Chapter 5. Physics, 4 th Edition James S. Walker. Copyright 2010 Pearson Education, Inc.

Lecture Outline Chapter 5 Physics, 4 th Edition James S. Walker Chapter 5 Newton s Laws of Motion Dynamics Force and Mass Units of Chapter 5 Newton s 1 st, 2 nd and 3 rd Laws of Motion The Vector Nature

Week 8 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

### Chapter 4. Forces I. 4.1 The Important Stuff Newton s First Law Newton s Second Law

Chapter 4 Forces I 4.1 The Important Stuff 4.1.1 Newton s First Law With Newton s Laws we begin the study of how motion occurs in the real world. The study of the causes of motion is called dynamics, or

### Physics 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

### Examples of Scalar and Vector Quantities 1. Candidates should be able to : QUANTITY VECTOR SCALAR

Candidates should be able to : Examples of Scalar and Vector Quantities 1 QUANTITY VECTOR SCALAR Define scalar and vector quantities and give examples. Draw and use a vector triangle to determine the resultant

### = 4.0 N. For the upper magnet, F L on U. T on U. because these are an action/ reaction pair. Equilibrium for the upper magnet requires n T on U

7.8. (a) The upper magnet is labeled U, the lower magnet L. Each magnet eerts a long-range magnetic force on the other. Each magnet and the table eert a contact force (normal force) on each other. In addition,

### If 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

### Physics 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

### Physics 590 Homework, Week 6 Week 6, Homework 1

Physics 590 Homework, Week 6 Week 6, Homework 1 Prob. 6.1.1 A descent vehicle landing on the moon has a vertical velocity toward the surface of the moon of 35 m/s. At the same time it has a horizontal

### B) 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

### TIME OF COMPLETION DEPARTMENT OF NATURAL SCIENCES. PHYS 1111, Exam 2 Section 1 Version 1 October 30, 2002 Total Weight: 100 points

TIME OF COMPLETION NAME DEPARTMENT OF NATURAL SCIENCES PHYS 1111, Exam 2 Section 1 Version 1 October 30, 2002 Total Weight: 100 points 1. Check your examination for completeness prior to starting. There

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

### Physics 11 Assignment KEY Dynamics Chapters 4 & 5

Physics Assignment KEY Dynamics Chapters 4 & 5 ote: for all dynamics problem-solving questions, draw appropriate free body diagrams and use the aforementioned problem-solving method.. Define the following

### Chapter 11 Equilibrium

11.1 The First Condition of Equilibrium The first condition of equilibrium deals with the forces that cause possible translations of a body. The simplest way to define the translational equilibrium of

### Mechanics 2. Revision Notes

Mechanics 2 Revision Notes November 2012 Contents 1 Kinematics 3 Constant acceleration in a vertical plane... 3 Variable acceleration... 5 Using vectors... 6 2 Centres of mass 8 Centre of mass of n particles...

### Physics 201 Fall 2009 Exam 2 October 27, 2009

Physics 201 Fall 2009 Exam 2 October 27, 2009 Section #: TA: 1. A mass m is traveling at an initial speed v 0 = 25.0 m/s. It is brought to rest in a distance of 62.5 m by a force of 15.0 N. The mass is

### Chapter 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

### Friction and Newton s 3rd law

Lecture 4 Friction and Newton s 3rd law Pre-reading: 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

### Practice Test SHM with Answers

Practice Test SHM with Answers MPC 1) If we double the frequency of a system undergoing simple harmonic motion, which of the following statements about that system are true? (There could be more than one

### Forces. 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.

### P113 University of Rochester NAME S. Manly Fall 2013

Final Exam (December 19, 2013) Please read the problems carefully and answer them in the space provided. Write on the back of the page, if necessary. Show all your work. Partial credit will be given unless

### PHYSICS 111 HOMEWORK SOLUTION #8. March 24, 2013

PHYSICS 111 HOMEWORK SOLUTION #8 March 24, 2013 0.1 A particle of mass m moves with momentum of magnitude p. a) Show that the kinetic energy of the particle is: K = p2 2m (Do this on paper. Your instructor

### PHYSICS 111 HOMEWORK SOLUTION #10. April 8, 2013

PHYSICS HOMEWORK SOLUTION #0 April 8, 203 0. Find the net torque on the wheel in the figure below about the axle through O, taking a = 6.0 cm and b = 30.0 cm. A torque that s produced by a force can be

### Forces: Equilibrium Examples

Physics 101: Lecture 02 Forces: Equilibrium Examples oday s lecture will cover extbook Sections 2.1-2.7 Phys 101 URL: http://courses.physics.illinois.edu/phys101/ Read the course web page! Physics 101:

### PHY231 Section 2, Form A March 22, 2012. 1. Which one of the following statements concerning kinetic energy is true?

1. Which one of the following statements concerning kinetic energy is true? A) Kinetic energy can be measured in watts. B) Kinetic energy is always equal to the potential energy. C) Kinetic energy is always

### Newton 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

### DISPLACEMENT AND FORCE IN TWO DIMENSIONS

DISPLACEMENT AND FORCE IN TWO DIMENSIONS Vocabulary Review Write the term that correctly completes the statement. Use each term once. coefficient of kinetic friction equilibrant static friction coefficient

### Conceptual Questions: Forces and Newton s Laws

Conceptual Questions: Forces and Newton s Laws 1. An object can have motion only if a net force acts on it. his statement is a. true b. false 2. And the reason for this (refer to previous question) is

### Newton 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

### CHAPTER 6 WORK AND ENERGY

CHAPTER 6 WORK AND ENERGY CONCEPTUAL QUESTIONS. REASONING AND SOLUTION The work done by F in moving the box through a displacement s is W = ( F cos 0 ) s= Fs. The work done by F is W = ( F cos θ). s From

### AP Physics - Chapter 8 Practice Test

AP Physics - Chapter 8 Practice Test Multiple Choice Identify the choice that best completes the statement or answers the question. 1. A single conservative force F x = (6.0x 12) N (x is in m) acts on

### Physics Exam 1 Review - Chapter 1,2

Physics 1401 - Exam 1 Review - Chapter 1,2 13. Which of the following is NOT one of the fundamental units in the SI system? A) newton B) meter C) kilogram D) second E) All of the above are fundamental

### SIMPLE HARMONIC MOTION

SIMPLE HARMONIC MOTION PURPOSE The purpose of this experiment is to investigate one of the fundamental types of motion that exists in nature - simple harmonic motion. The importance of this kind of motion

### What 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

### When showing forces on diagrams, it is important to show the directions in which they act as well as their magnitudes.

When showing forces on diagrams, it is important to show the directions in which they act as well as their magnitudes. mass M, the force of attraction exerted by the Earth on an object, acts downwards.

### COEFFICIENT OF KINETIC FRICTION

COEFFICIENT OF KINETIC FRICTION LAB MECH 5.COMP From Physics with Computers, Vernier Software & Technology, 2000. INTRODUCTION If you try to slide a heavy box resting on the floor, you may find it difficult

### STATIC AND KINETIC FRICTION

STATIC AND KINETIC FRICTION LAB MECH 3.COMP From Physics with Computers, Vernier Software & Technology, 2000. INTRODUCTION If you try to slide a heavy box resting on the floor, you may find it difficult