Ch4_TomasofskyN

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 * Chapter 4 **

** PC Newton's Law: Lesson 1 **
Chapter 1: Newton's First Law of Motion

a. **Newton's First Law**
 * What is Newton's First Law?
 * Object at rest stays at rest
 * Object in motion stays in motion
 * Same speed, same direction
 * Unless an unbalanced force acts on it
 * [[image:Screen_shot_2011-11-14_at_1.41.06_PM.png]]
 * Things tend to keep on doing what they're doing
 * Ex:
 * Seatbelts, Coffee in a Car

b. **Inertia and Mass**
 * How do Inertia and Mass Relate?
 * **Inertia**: The natural tendency for objects to resist changes in their state of motion
 * Developed by Galileo but varies from Newton's definition
 * Some objects have more of a tenency to resist changes than others
 * ** MASS **
 * The more inertia, the more mass --> the more mass, the more inertia

c. **State of Motion**
 * What does State of Motion apply to?
 * Defined by velocity
 * **Inertia**: tendency of an object to resist changes in its __ velocity __ / __ acceleration __
 * Objects will not change their STATE OF MOTION unless acted on by an unbalanced force

d. **Balanced and UnBalanced forces**
 * What is the difference between a balanced and unbalanced force?
 * **Balanced Forces**: Forces of equal magnitude in opposite directions
 * Create __ Equilibrium __
 * No acceleration possible
 * **Unbalanced Force**: Forces of different magnitude in opposite/same directions
 * Cause acceleration
 * [[image:Screen_shot_2011-11-14_at_3.48.23_PM.png]]<---balanced force

PC Newton's Law: Lesson 2
Chapter 2: Force and Its Representation

a.**The Meaning of Force**
 * What is force?
 * __Force__: Push or pull upon an object (from interaction with other)
 * Interaction = force
 * Contact Force
 * Physical contact (friction, tension, normal, air, applied)
 * Action-at-a-Distance Force
 * Not in physical contact (gravity)
 * Newton's (N)
 * 1 N = 1 kg * m/s2
 * Vector quantity ^^ Use Newtons

b. **Types of Forces**
 * What is the difference between types of forces?
 * Gravitational Force
 * Weight of the object (force = weight)
 * Directed downward towards center of the earth
 * *Mass is not Weight!!!
 * Mass = matter
 * Weight = Force of gravity
 * Normal Force
 * Support force when there is contact
 * Upward (sometimes horizontal)
 * Friction Force
 * Motion
 * Sliding + Static (Depends on nature of object)
 * Opposite of motion of object
 * Tension
 * String, rope, cable, wire
 * Along length of thing pulling it
 * Pulls equally on opposite ends

c. **Drawing Free-Body Diagrams**
 * How do you draw a free body diagram?
 * Show all forces (w/ magnitude)
 * Box, then draw arrows in right direction with right size length

d. **Determining the Net Force**
 * How do you determine the net force?
 * Unbalanced force: Does not cancel out with other forces
 * Causes acceleration
 * **Net force**: Vector sum of all forces on object

PC Newton's Law: Lesson 3 A+B
Chapter 3: Newton's Second Law of Motion

a. **Newton's Second Law**
 * What does Newton's Second Law state?
 * **Second Law:** The Acceleration of an object is dependent on the net force and the mass
 * Unbalanced forces
 * More force = More Acceleration
 * More Mass= Less Acceleration
 * Fnet = m * a
 * ** Net force: ** Vector sum of all forces
 * Acceleration is inversely proportional to mass
 * Doubling mass = halving the acceleration
 * Halving mass = doubling acceleration
 * Acceleration is directly proportional to force

b. **The Big Misconception**
 * What is the Big Misconception?
 * Understand meaning and believe in implications
 * **Misconception**: Motion requires a continued force

** PC: Vectors: Lesson 3 **
a. Addition of Forces > b.Resolution of Forces > c. Equilibrium and Statics d. Net Force Problems Revisited e. Inclined Planes >>> f. Double Take (a.k.a. Two Body Problems) >>>
 * How do you add forces in two dimension?
 * Purpose is to to find the net force when it has forces both horizontal and vertical
 * Goal is to find the net force and the corresponding acceleration
 * Head to tail method (to form a triangle)
 * What if the force is not horizontal or vertical?
 * Diagonal forces can be broken up into two components
 * Vertical + Horizontal component
 * Trig can then be applied to find influence of a single vector
 * SOH-CAH-TOA
 * Only the angle with the horizontal changes
 * Angle increases, force decreases (on horizontal)
 * What is static equilibrium
 * __ Equilibrium __ : Forces are balanced by leftward and rightward forces
 * All forces do not have to be equal to each othe rin equilibrium
 * Think balanced!
 * __ Static Equilibrium: __ Stationary or at rest; do not move now
 * Resultant should be 0 N!
 * ex: Hanging up a painting, Tension holding a sign up
 * How do you find the net force of an object?
 * When there are components to the force
 * Add together forces as vectors, divide the net force by mass
 * Acceleration is the answer
 * Trig relations simplified (find two components)
 * What is the difference when solving inclined plane problems
 * Rate at how it slides down is dependent on how tilted the surface is
 * Always at least two forces
 * [[image:Screen_shot_2011-12-11_at_12.46.16_PM.png]]
 * any force directed at an angle to the horizontal is into two components
 * Gravity force
 * Solve like any other net force problem (remember the incline!)
 * How Do you solve a two body problem?
 * Acceleration of an object and force acting between object
 * System can be used
 * Pulley diagrams
 * Pulling on one string will change the movement
 * Changes force
 * [[image:Screen_shot_2011-12-11_at_12.49.42_PM.png]]
 * Accelerate at same rate
 * Can consider whole thing as one system
 * Systematic approach
 * Always draw free body diagram
 * Newton's second law application