Ch4_LeibowitzG

= **__ Lesson 1- __****// Newton's First Law of Motion //** = toc
 * **Newton's First Law**
 * **Inertia and Mass**
 * **State of Motion**
 * **Balanced and Unbalanced Forces**

__**Newton's First Law** __ **What is Newton’s first law of motion? Explain in detail.** - Isaac Newton: 17th century scientist that put forth a variety of laws that explain why objects move as they do, known as Newton’s Three Laws of Motion - First: __Law of Inertia__: an object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force - Two parts to statement- one predicts behavior of stationary objects while the other predicts behavior of moving objects
 * Objects tend to maintain the same state of motion unless acted upon by an unbalanced force
 * Natural tendency of objects to resist changes in their state of motion and tend to “keep doing what they’re doing”

**How can you apply Newton’s First Law of Motion to everyday life?** - Ex: inertia in an automobile while it is braking to a stop - Force of road on the locked wheels provides the unbalanced force to change the car’s state of motion BUT there is no unbalanced force to change your own state of motion
 * You continue in motion, sliding along the seat in forward motion
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">A person in motion stays in motion with the same speed and same direction //unless acted upon by the unbalanced force// of a seat belt

<span style="color: #ff0000; font-family: 'Times New Roman',Times,serif; font-size: 120%;">* This section of the reading provides a explanation for Newton's first law of motion, the law of inertia, which states that an object at rest stays at rest and an object in motion stays in motion unless acted upon by an unbalanced force. This is the basic definition for this law. It goes further to relate this law to everyday life, and gives the example of a car breaking and the presence of a seatbelt to instill this concept within the reader.

__<span style="font-family: 'Times New Roman',Times,serif; font-size: 16px;">**Inertia and Mass** __ <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">**What is inertia?** <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">- **Inertia:** the resistance an object has to change in its state of motion <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">- Challenged common belief that the natural tendency of objects was to come to a rest position

<span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">**How did Galileo play a role in the concept of inertia?** <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">- Galileo: 17th century premier scientist that developed the concept of inertia <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">- Reasoned that moving objects eventually stop because of the force friction <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">- Newton built on Galileo’s thoughts in his first law of motion
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">A force is __not__ needed to keep an object in motion
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">The force brings the object to rest

<span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">**Explain how mass and inertia are related.** <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">- Tendency of an object to resist changes in its state of motion varies with mass <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">- **Mass:** quantity that is solely dependent upon the inertia of an object
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">The more inertia an object has, the more mass it has
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">A more massive object has a greater tendency to resist change

<span style="color: #ff0000; font-family: 'Times New Roman',Times,serif; font-size: 120%;">* This section of the reading focuses on the concept of inertia and the role it plays in Newton's first law of motion. It first defines inertia with the basic definition of the resistance an object has to change in its state of motion. It briefly covers Galileo, who helped develop this concept and explains how Newton built upon Galileo's beliefs, clarifying that the force is not needed to keep in object in motion, but rather brings it to rest. Finally it defines the term, mass, and explains its positive correlation.

__<span style="font-family: 'Times New Roman',Times,serif; font-size: 16px;">**State of Motion** __ <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">**What is it meant by the state of motion of an object?** <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">- State of motion of an object is defined by its **velocity** <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">- **Velocity:** the speed with a direction
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">Inertia- tendency of an object to resist changes in its velocity OR resist acceleration
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">Object at rest= 0 velocity (O m/s/s)

<span style="color: #ff0000; font-family: 'Times New Roman',Times,serif; font-size: 120%;">* This section of the reading focuses on an object's state of motion, which is defined by its velocity, a concept we learned in previous chapters. It then redefines the concept taught in the last section, inertia. Inertia could basically be thought of as the tendency of an object to resist changes in its velocity or to resist acceleration.

__<span style="font-family: 'Times New Roman',Times,serif; font-size: 16px;">**Balanced and Unbalanced Forces** __ <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">**What is the difference between balanced and unbalanced forces** <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">- **Balanced forces:** forces are of equal magnitude and opposite direction <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">- **Unbalanced forces:** forces are NOT balanced by a force of equal magnitude in the opposite direction
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">At __equilibrium__
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">Maintains state of motion
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">Does not accelerate
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">Changes state of motion
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">Cause accelerations

<span style="color: #ff0000; font-family: 'Times New Roman',Times,serif; font-size: 120%;">* This section of the reading centers upon the difference between balanced and unbalanced forces. Balance forces are forces of equal magnitude in the opposite direction, while unbalanced forces are the opposite. Balanced forces, at a state of equilibrium, will not change their state of motion or accelerate, while unbalanced forces do both.

=**__ Lesson 2- __****// Force and Its Representation //**=
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">**The Meaning of Force**
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 16px; line-height: 24px;">**Types of Forces**
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 16px; line-height: 24px;">**Drawing Free-Body Diagrams**
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 16px; line-height: 24px;">**Determining the Net Force**

<span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">**__The Meaning of Force__** <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">**What is the meaning of force?** <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">- **Force:** push or pull upon an object resulting from the object’s interaction with another object <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">- Interaction stops --> two objects no longer experience the force <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">- Forces ONLY exist as a result of an interaction <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">- Two categories: contact forces and forces resulting from action-at-a-distance <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">- **Contact forces:** types of forces that result when two interacting objects are physically contacting each other (ex: friction, tension, normal…) <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">- **Action-at-a-distance forces:** types of forces that result when the two interacting objects are not in physical contact with each other, YET are able to exert a push or pull (ex: sun and planets’ gravitation pull) <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">- * A force is a vector quantity (magnitude and direction)

<span style="color: #ff0000; font-family: 'Times New Roman',Times,serif; font-size: 120%;">* This section of the reading introduces a basic definition of a force, which is a push or pull upon an object resulting from the object's interaction with another. It goes on to explain the relationship between an interaction and a force, in which a force depends on an interaction. It goes into detail about two different types of forces, one that result from physical contact between objects, a contact force, and the other which occurs without physical contact, an action-at-a-distance force.

<span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">**__Types of Forces__** <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">**What are the many different types of forces?** <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">- Applied force, gravitational force, normal force, frictional force, air resistance force, tension force, spring force <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">- **Applied:** force that is applied to an object by a person or another object <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">- **Gravitation:** force with which the earth, moon, or other massively large object attracts another object towards itself <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">- **Normal:** support force exerted upon an object that is in contact with another stable object <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">- **Friction:** force exerted by a surface as an object moves across it <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">- **Air resistance:** force that acts upon objects as they travel through air <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">- **Tension:** force that is transmitted through a string, rope, cable, or wire when it is pulled tight by forces acting from opposite ends <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">- **Spring:** force exerted by a compressed or stretched spring upon any object that is attached to it

<span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">**What is the confusion of mass and weight?** <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">- **Weight:** force of gravity acting upon an object (dependent on value of g) <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">- **Mass:** the amount of matter that is contained by the object

<span style="color: #ff0000; font-family: 'Times New Roman',Times,serif; font-size: 120%;">* After the previous section defined the term force, this section focuses on the many different types of forces and gives a basic definition for each, point out the differences. An example of an important force in the reading is a normal force, which is a force exerted upon an object in contact with another. It goes on to explain other key forces, such as friction and tension. It concludes with clarifying the difference between weight, a force of gravity, and mass, an amount of matter.

<span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">**__Drawing Free-Body Diagrams__** <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">**How does one draw free body diagrams?** <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">- **Free-body diagrams:** diagrams used to show the relative magnitude and direction of all forces acting upon an object in a given situation <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">- Size of arrow reflects magnitude of force <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">- Direction of arrow shows direction that the force is acting <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">- Each arrow is labeled to indicate type of force

<span style="color: #ff0000; font-family: 'Times New Roman',Times,serif; font-size: 120%;">* This section of the reading explained free-body diagrams, diagrams who's purpose is to illustrate magnitude and direction of the forces acting on an object. It discusses things to take into consideration when drawing the diagrams, such as arrow size, direction of arrow, and label of arrow.

<span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">**__Determining the Net Force__** <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">**What is a net force and how does one determine it?** <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">- **Net force:** the vector sum of all the forces that act upon an object <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">- Determined by adding up all individual vectors <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">- Two forces of equal magnitude and opposite direction will cancel each other out <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">- An unbalanced force is a net force à net forces cause accelerations

<span style="color: #ff0000; font-family: 'Times New Roman',Times,serif; font-size: 120%;">* This section of the reading defines a net force, the vector sum of all forces acting on an object, and explains how to determine it when given a situation. You do this by adding up the individual vectors and canceling out forces of equal magnitude BUT opposite direction will cancel each other out.

=**__ Lesson 3- __****// Newton's Second Law of Motion (A+B) //**=
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 16px; line-height: 24px;">**Newton's Second Law**
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 16px; line-height: 24px;">**The Big Misconception**

<span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">**__Newton’s Second Law__** <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">**What is Newton’s Second Law of Motion? Explain in detail.** <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">- Newton’s Second Law: the acceleration of an object is dependent upon two variables- the __net force__ acting upon the object and the mass of the object <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">- Acceleration of object depends directly upon the net force acting on object, and inversely upon the mass of object <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">- Net force acting upon the object is increased = acceleration is increased <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">- Mass of an object is increased = acceleration is decreased <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">- A= F(net) / m OR F(net) = m*a <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">- * It is the NET FORCE that is related to acceleration, not just any force <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">- A unit of force is equal to a unit of mass times a unit of acceleration- 1 Newton = 1kg * m/s^2

<span style="color: #ff0000; font-family: 'Times New Roman',Times,serif; font-size: 120%;">* This section of the reading focuses on Newton’s Second Law of Motion, which provides the explanation for the behavior of objects upon which the forces do not balance. This law states that unbalanced forces cause objects to accelerate with an acceleration that is directly proportional to the net force and inversely proportional to the mass. It provides an equation for this concept. It makes a distinct difference between a net force and any other force and emphasizes the fact that it is the net force, which Newton’s Second Law is centered upon.

<span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">- Misconception- idea that sustaining motion requires a continued force (NO!) <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">- A net force (an unbalanced force) causes an acceleration NOT motion <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">- The acceleration is the same direction as the net force <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">- An object can be moving to the right even if the only forces acting upon the object are vertical forces
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">__The Big Misconception__ **
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;"> What is the “big misconception” and what is the truth behind it? **

<span style="color: #ff0000; font-family: 'Times New Roman',Times,serif; font-size: 120%;">* This section of the reading addresses a major misconception amongst physics students, that force is required for motion. This is false, and in fact, a net force causes acceleration not motion.