Chapter 6 Forces Contact vs Long Range Force
![Chapter 6 Forces Chapter 6 Forces](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-1.jpg)
![Contact vs. Long Range Force • A contact force acts on an object only Contact vs. Long Range Force • A contact force acts on an object only](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-2.jpg)
![Practice Problems • Do Practice Problems on page 119 of textbook. What forces are Practice Problems • Do Practice Problems on page 119 of textbook. What forces are](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-3.jpg)
![Newton’s Second Law of Motion • How does an object move when one or Newton’s Second Law of Motion • How does an object move when one or](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-4.jpg)
![How does acceleration depend upon the force? • Based on the rubber band lab, How does acceleration depend upon the force? • Based on the rubber band lab,](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-5.jpg)
![How does acceleration depend upon the object? • What happens if the object changes? How does acceleration depend upon the object? • What happens if the object changes?](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-6.jpg)
![Combining Forces • What if two or more rubber bands exert forces on a Combining Forces • What if two or more rubber bands exert forces on a](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-7.jpg)
![Combining Forces Continued. . • The vector sum of two or more forces acting Combining Forces Continued. . • The vector sum of two or more forces acting](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-8.jpg)
![Measuring Force: the Newton • Because force is equal to mass times acceleration, one Measuring Force: the Newton • Because force is equal to mass times acceleration, one](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-9.jpg)
![Practice Problems • Do the Practice Problems on page 122. 2 -6. Practice Problems • Do the Practice Problems on page 122. 2 -6.](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-10.jpg)
![Newton’s st 1 Law of Motion • “An object that is at rest will Newton’s st 1 Law of Motion • “An object that is at rest will](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-11.jpg)
![Newton’s 1 st Law of Motion Continued. . • If the net force on Newton’s 1 st Law of Motion Continued. . • If the net force on](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-12.jpg)
![Practice Problems • Do practice problems 7 -11 on page 124. Practice Problems • Do practice problems 7 -11 on page 124.](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-13.jpg)
![Common Misconceptions. . • Inertia is a force. Not true. • A force is Common Misconceptions. . • Inertia is a force. Not true. • A force is](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-14.jpg)
![6. 2 Using Newton’s Laws • Newton formulated his laws over 300 years ago. 6. 2 Using Newton’s Laws • Newton formulated his laws over 300 years ago.](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-15.jpg)
![Using Newton’s nd 2 Law • Aristotle believed that the heavier an object is Using Newton’s nd 2 Law • Aristotle believed that the heavier an object is](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-16.jpg)
![Mass and Weight • Galileo often used something called “thought experiments”. • Look at Mass and Weight • Galileo often used something called “thought experiments”. • Look at](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-17.jpg)
![Scales • Do scales measure mass or weight? • Look at figure 6 -6 Scales • Do scales measure mass or weight? • Look at figure 6 -6](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-18.jpg)
![Example and practice problems • Read through the example problems on page 128. • Example and practice problems • Read through the example problems on page 128. •](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-19.jpg)
![Apparent Weight • Apparent weight is the force exerted by the scale. • Weightlessness Apparent Weight • Apparent weight is the force exerted by the scale. • Weightlessness](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-20.jpg)
![The Friction Force • Static friction force is the force that is exerted on The Friction Force • Static friction force is the force that is exerted on](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-21.jpg)
![Calculating friction forces • We assume that friction depends on the surfaces in contact, Calculating friction forces • We assume that friction depends on the surfaces in contact,](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-22.jpg)
![Continued. . • Example problems pg. 131 -132. • Do practice problems 14 -16 Continued. . • Example problems pg. 131 -132. • Do practice problems 14 -16](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-23.jpg)
![Air drag and terminal velocity • When an object moves through air or any Air drag and terminal velocity • When an object moves through air or any](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-24.jpg)
![Terminal velocity • Terminal velocity can change and does change for different objects. • Terminal velocity • Terminal velocity can change and does change for different objects. •](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-25.jpg)
![Periodic Motion • Two quantities describe simple harmonic motion. • Period- the time needed Periodic Motion • Two quantities describe simple harmonic motion. • Period- the time needed](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-26.jpg)
![The pendulum • Look at the equation on page 135. Copy it into your The pendulum • Look at the equation on page 135. Copy it into your](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-27.jpg)
![6. 3 Interaction Forces • Interaction forces are the forces working in a system. 6. 3 Interaction Forces • Interaction forces are the forces working in a system.](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-28.jpg)
![Newton’s Third Law • An interaction pair is the two forces that are in Newton’s Third Law • An interaction pair is the two forces that are in](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-29.jpg)
![Practice Problems • Practice problems on page 141. Practice Problems • Practice problems on page 141.](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-30.jpg)
![Four Fundamental Forces • Find and share with class. Four Fundamental Forces • Find and share with class.](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-31.jpg)
![Forces of Ropes and Strings • Read and sumarize. Pg. 143 Forces of Ropes and Strings • Read and sumarize. Pg. 143](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-32.jpg)
- Slides: 32
![Chapter 6 Forces Chapter 6 Forces](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-1.jpg)
Chapter 6 Forces
![Contact vs Long Range Force A contact force acts on an object only Contact vs. Long Range Force • A contact force acts on an object only](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-2.jpg)
Contact vs. Long Range Force • A contact force acts on an object only by touching it. Ex. You touching a book. Desk on the ground. • A long-range force is exerted without contact. Ex. Gravity. • Each force has a specific, identifiable, immediate cause called the agent.
![Practice Problems Do Practice Problems on page 119 of textbook What forces are Practice Problems • Do Practice Problems on page 119 of textbook. What forces are](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-3.jpg)
Practice Problems • Do Practice Problems on page 119 of textbook. What forces are acting on each object?
![Newtons Second Law of Motion How does an object move when one or Newton’s Second Law of Motion • How does an object move when one or](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-4.jpg)
Newton’s Second Law of Motion • How does an object move when one or more forces are exerted on it? • We will start by looking at motion horizontally and ignoring friction. • Look at figure 6 -2 a and 6 -2 b. Why is the velocity vs. time graph constant?
![How does acceleration depend upon the force Based on the rubber band lab How does acceleration depend upon the force? • Based on the rubber band lab,](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-5.jpg)
How does acceleration depend upon the force? • Based on the rubber band lab, we could plot the force exerted vs the acceleration of the cart. • We notice that the acceleration (a) is proportional with the force (F) exerted. • The larger the force, the greater the acceleration. • Linear relationship: F= ka ; k is the slope of the line.
![How does acceleration depend upon the object What happens if the object changes How does acceleration depend upon the object? • What happens if the object changes?](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-6.jpg)
How does acceleration depend upon the object? • What happens if the object changes? We put a second cart on top of the first. Then a third. • Look at figure 6 -3 b: What do you see? • The acceleration of 2 carts is ½ the acceleration of 1 cart. • So therefore, the slope of the lines depends upon the mass. More mass requires more force. • Mass is the slope: F=ma
![Combining Forces What if two or more rubber bands exert forces on a Combining Forces • What if two or more rubber bands exert forces on a](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-7.jpg)
Combining Forces • What if two or more rubber bands exert forces on a cart? In the same direction or in opposite directions? • We show the different forces acting on an object by using a free-body diagram. • Because forces are vectors, the total force on an object is the vector sum of all the forces exerted on the object.
![Combining Forces Continued The vector sum of two or more forces acting Combining Forces Continued. . • The vector sum of two or more forces acting](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-8.jpg)
Combining Forces Continued. . • The vector sum of two or more forces acting on an object is call the net force. • Experiments show that acceleration of an object is proportional to the net force exerted on the object and inversely proportional to the mass of the object being accelerated. • This is Newton’s 2 nd Law: a= Fnet/m or F=ma
![Measuring Force the Newton Because force is equal to mass times acceleration one Measuring Force: the Newton • Because force is equal to mass times acceleration, one](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-9.jpg)
Measuring Force: the Newton • Because force is equal to mass times acceleration, one force unit has the dimensions 1 kg x m/s^2. • The unit of force in the SI system is the newton, N.
![Practice Problems Do the Practice Problems on page 122 2 6 Practice Problems • Do the Practice Problems on page 122. 2 -6.](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-10.jpg)
Practice Problems • Do the Practice Problems on page 122. 2 -6.
![Newtons st 1 Law of Motion An object that is at rest will Newton’s st 1 Law of Motion • “An object that is at rest will](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-11.jpg)
Newton’s st 1 Law of Motion • “An object that is at rest will remain at rest or an object that is moving will continue to move in a straight line with constant speed, if and only if the net force acting on that object is zero. ” Newton’s 1 st Law of Motion • Often called the Law of Inertia: Inertia is the tendency of an object to resist change.
![Newtons 1 st Law of Motion Continued If the net force on Newton’s 1 st Law of Motion Continued. . • If the net force on](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-12.jpg)
Newton’s 1 st Law of Motion Continued. . • If the net force on an object is zero, the object is in equilibrium. • Equilibrium happens when an object is at rest or is moving at a constant velocity. • Copy Table 6 -2 in your notes: Some Types of Forces.
![Practice Problems Do practice problems 7 11 on page 124 Practice Problems • Do practice problems 7 -11 on page 124.](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-13.jpg)
Practice Problems • Do practice problems 7 -11 on page 124.
![Common Misconceptions Inertia is a force Not true A force is Common Misconceptions. . • Inertia is a force. Not true. • A force is](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-14.jpg)
Common Misconceptions. . • Inertia is a force. Not true. • A force is needed to keep an object moving. Not true.
![6 2 Using Newtons Laws Newton formulated his laws over 300 years ago 6. 2 Using Newton’s Laws • Newton formulated his laws over 300 years ago.](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-15.jpg)
6. 2 Using Newton’s Laws • Newton formulated his laws over 300 years ago. • They still explain everyday motion!
![Using Newtons nd 2 Law Aristotle believed that the heavier an object is Using Newton’s nd 2 Law • Aristotle believed that the heavier an object is](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-16.jpg)
Using Newton’s nd 2 Law • Aristotle believed that the heavier an object is the faster it falls. • Is this true? Why or Why not?
![Mass and Weight Galileo often used something called thought experiments Look at Mass and Weight • Galileo often used something called “thought experiments”. • Look at](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-17.jpg)
Mass and Weight • Galileo often used something called “thought experiments”. • Look at figure 6 -5. • A ball that is falling freely without air resistance has a weight that is equal to its mass times it acceleration.
![Scales Do scales measure mass or weight Look at figure 6 6 Scales • Do scales measure mass or weight? • Look at figure 6 -6](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-18.jpg)
Scales • Do scales measure mass or weight? • Look at figure 6 -6 b. • When you step on the scale, the scale exerts an upward force on you. • A spring scale measures weight not mass. • If you were on a different planet, the compression of the spring would be different, therefore your weight would change but not your mass.
![Example and practice problems Read through the example problems on page 128 Example and practice problems • Read through the example problems on page 128. •](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-19.jpg)
Example and practice problems • Read through the example problems on page 128. • Then try Practice Problems 12 -13 on page 129.
![Apparent Weight Apparent weight is the force exerted by the scale Weightlessness Apparent Weight • Apparent weight is the force exerted by the scale. • Weightlessness](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-20.jpg)
Apparent Weight • Apparent weight is the force exerted by the scale. • Weightlessness does not mean your weight is zero. It means that there are no contact forces pushing up on you. Your apparent weight is zero.
![The Friction Force Static friction force is the force that is exerted on The Friction Force • Static friction force is the force that is exerted on](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-21.jpg)
The Friction Force • Static friction force is the force that is exerted on one surface by the other when there is no relative motion between the two surfaces. • The static friction force can only grow so large. Eventually the object will move. • The Kinetic Friction Force is the force exerted on one surface by the other when the surfaces are in relative motion.
![Calculating friction forces We assume that friction depends on the surfaces in contact Calculating friction forces • We assume that friction depends on the surfaces in contact,](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-22.jpg)
Calculating friction forces • We assume that friction depends on the surfaces in contact, but not on the area of the surfaces nor the speed of their relative motion. • Kinetic Friction Force Ff, Kinetic = μk F N • μk is a proportionality constant called the kinetic coefficient of friction. • Static Friction Force • Copy table 6 -3
![Continued Example problems pg 131 132 Do practice problems 14 16 Continued. . • Example problems pg. 131 -132. • Do practice problems 14 -16](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-23.jpg)
Continued. . • Example problems pg. 131 -132. • Do practice problems 14 -16 on page 133.
![Air drag and terminal velocity When an object moves through air or any Air drag and terminal velocity • When an object moves through air or any](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-24.jpg)
Air drag and terminal velocity • When an object moves through air or any other fluid, the fluid exerts a friction like force on the moving object. • This type of friction depends on the speed of the object. • Think about dropping a tennis ball from a tower. • The constant velocity that is reached when the drag force equals the force of gravity (no net force)
![Terminal velocity Terminal velocity can change and does change for different objects Terminal velocity • Terminal velocity can change and does change for different objects. •](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-25.jpg)
Terminal velocity • Terminal velocity can change and does change for different objects. • It depends on size and shape of the object.
![Periodic Motion Two quantities describe simple harmonic motion Period the time needed Periodic Motion • Two quantities describe simple harmonic motion. • Period- the time needed](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-26.jpg)
Periodic Motion • Two quantities describe simple harmonic motion. • Period- the time needed to repeat one complete cycle of motion. • Amplitude- the maximum distance the object moves form equilibrium.
![The pendulum Look at the equation on page 135 Copy it into your The pendulum • Look at the equation on page 135. Copy it into your](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-27.jpg)
The pendulum • Look at the equation on page 135. Copy it into your notes and on your equation index card. • Notice that the period depends only upon the length of the pendulum and the acceleration due to gravity, not on the mass of the boob or the amplitude of oscillation.
![6 3 Interaction Forces Interaction forces are the forces working in a system 6. 3 Interaction Forces • Interaction forces are the forces working in a system.](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-28.jpg)
6. 3 Interaction Forces • Interaction forces are the forces working in a system. • Think about when you thrown a baseball. • There are two forces: your hand on the ball and the ball on your hand. • What are the directions and magnitudes of these forces?
![Newtons Third Law An interaction pair is the two forces that are in Newton’s Third Law • An interaction pair is the two forces that are in](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-29.jpg)
Newton’s Third Law • An interaction pair is the two forces that are in opposite directions and have equal magnitude. • So the magnitude of the force of your hand on the ball equals that of the ball on your hand. • Newton’s Third Law- states all forces come in pairs. Every action has an equal and opposite reaction.
![Practice Problems Practice problems on page 141 Practice Problems • Practice problems on page 141.](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-30.jpg)
Practice Problems • Practice problems on page 141.
![Four Fundamental Forces Find and share with class Four Fundamental Forces • Find and share with class.](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-31.jpg)
Four Fundamental Forces • Find and share with class.
![Forces of Ropes and Strings Read and sumarize Pg 143 Forces of Ropes and Strings • Read and sumarize. Pg. 143](https://slidetodoc.com/presentation_image/a7377c572d8ed335ccb24637b9e6651b/image-32.jpg)
Forces of Ropes and Strings • Read and sumarize. Pg. 143
Long range force
Which is a contact force? *
Tension force contact or noncontact
Contact and noncontact forces
Air resistance contact force
Examples of non contact force
Which of the following forces is a contact force? *
As compared to long-range forecasts, short-range forecasts
Air resistance contact or noncontact force
Tall + short h
Once upon a time there lived a boy
Sliding contact bearing
Irritant contact dermatitis vs allergic contact dermatitis
Dangling bond in fullerene
Service marketing chapter 2
Is drag a contact force
Is pressure a contact force
Is air resistance a non contact force
Is friction a contact force
Friction is a necessary evil
Why is gravity a non contact force
Friction and air resistance
Tug of war or tug-of-war
Is upthrust a contact or noncontact force
Buoyancy force contact or noncontact
Is drag a contact force
Find the resultant of two like parallel forces
The forces shown above are
Intermolecular forces from strongest to weakest
Difference between intermolecular and intramolecular
Inter vs intramolecular forces
Balanced forces and unbalanced forces venn diagram
Is deposition constructive or destructive