Ch4_CaspertS

toc __**Homework - Lesson 1 (a-d) - Newton's First Law of Motion**__
 * 1) (a) What is **Newton's First Law of Motion** ?
 * 2) Also known as the Law of Inertia
 * 3) An object at rest stays at rest or an object in motion stays in motion with the same speed in the same line until acted upon by an unbalanced force
 * 4) Simple terms: No change in motion unless an unbalanced force causes it
 * 5) Otherwise move at constant speed in a straight line
 * 6) Galileo came up with it with his rolling ball experiment
 * 7) Newton just cleaned it up / perfected it
 * 8) (b) What are inertia and mass?
 * 9) **Inertia** - the natural tendency of an object to resist changes in its state of motion
 * 10) A property of matter
 * 11) Measures how difficult it is to change an object's motion
 * 12) **Mass** - the quantity that is solely dependent upon the inertia of an object
 * 13) The more inertia an object has, the more mass it has; visa-vera
 * 14) Base unit of mass is (kg)
 * 15) **Weight** is a force, pull of gravity on a mass
 * 16) Base unit of weight is (N)
 * 17) On Earth g=9.8 m/s^2
 * 18) Weight = m*g
 * 19) X + Y components are independent of each other
 * 20) Force (x) = mass X acceleration (x)
 * 21) Force (y) = mass X acceleration (y)
 * 22) Force and acceleration have a direction relationship
 * 23) Mass and acceleration have an inverse relationship
 * 24) (c) What is meant by the state of motion of an object?
 * 25) State of motion of an object is defined by its velocity (speed & direction)
 * 26) (d) What is the difference between balanced and unbalanced forces?
 * 27) Balanced forces point in the opposite direction and have the same magnitude
 * 28) The object between the forces is at equilibrium & will not accelerate
 * 29) 2 types of equilibrium:
 * 30) Static - no motion at all, occurs at rest
 * 31) Dynamic - constant speed
 * 32) When there aren't 2 or more forces balancing each other out, there is an unbalanced force
 * 33) Will cause the object to accelerate/decelerate
 * 34) **Newton's 2nd Law of Motion** - When an unbalnced force acts on an object, it will accelerate in the direction of the unbalanced force.

__**Homework - Lesson 2 (a-d) - Force and Its Representation**__
 * 1) What is meant by force?
 * 2) ** Force ** - push or pull upon an object
 * 3) Results from the object's interaction with another object
 * 4) When the interaction ends, so does the force between the 2 objects
 * 5) Forces ONLY exist as a result of an interaction
 * 6) What are the different types of forces?
 * 7) **Contact Forces** - when 2 objects are physically interacting iwth each other
 * 8) Frictional forces - force exerted by surface as an object moves/tries to move across it
 * 9) Tensional forces - force that is transmitted through string, rope, cable or wire when pulled tight from opposite ends
 * 10) Normal forces - support force exerted upon object in contact w/ another stable object
 * 11) Air Resistance forces - type of frictional force that acts upon object as it travels through air
 * 12) Applied forces - applied to an object by a person or another object
 * 13) Spring forces - exerted by compressed or stretched spring upon any object that is attatched to it
 * 14) Action-at-a-Distance Forces - when 2 interacting objects are not physically touching each other, but are able to exert a push or pull
 * 15) Gravitational forces- force with which the earth, moon, etc. attracts another object toward itself
 * 16) Also known as weight
 * 17) F(grav) = m*g[[image:http://www.physicsclassroom.com/Class/newtlaws/u2l2c1.gif width="198" height="184" align="right"]]
 * 18) Electrical forces
 * 19) Magnetic forces
 * 20) What does a **free-body diagram** show?
 * 21) It shows the relative magnitude and direction of all forces acting upon an object in a certain situation
 * 22) How do you determine the net force of multiple forces?
 * 23) If all the vertical forces or all the horizontal forces don't cancel each other out, an unbalanced force exists
 * 24) Equal to the sum of all the forces that act upon an object

__**Homework - Ch.4 page 97 #1-5,9,10,11,18**__ 1. The unbalanced force is acting on the wagon, not the child. So the wagon is moving while the child is staying in place. 2. (a) Mary sees the the truck moving forward and the box just staying in the same place. (b) Chris sees him staying in the same place and the box moving backward. 3. No. When forces are balanced it causes an object at rest to stay at rest and an object in motion to stay in motion with a constant speed. In both of these there are forces but the acceleration is 0. 4. When one forces acts on an object it is unbalanced and cannot have an acceleration of 0. However, it could have a velocity of 0, for example at the top of a projectile. 5. (a/b) Yes, there is a normal force between the ground and golf ball that makes it bounce back up. 9. With a sharp pull the thread is likely to break below the stone. With a long and steady pull it is likely to break above the stone. 10. An object's fall is not dependent on the weight or mass of an object. Instead, it is dependent on the surface area area of the object. So if the 1-kg and 2-kg rocks are the same size, then they will fall at the same speed. 11. (a) Yes, because pounds is a measure of force. (b) No, because kilograms is a measurement of mass which is independent of gravity 18. When a car is hit from behind the car suddenly moves at a quicker velocity than both the person and car were originally going. So when it is hit, the body of the person moves forward like the head stays in the same place eventually hitting the seat.

__**Homework - Lesson 3 (a-b) - Newton's Second Law of Motion**__
 * 1) What is Newton's Second Law?
 * 2) It states that the acceleration of an object is dependent upon 2 variables:
 * 3) Net Force acting upon the object
 * 4) Mass of the Object
 * 5) Net Force = Mass * Acceleration
 * 6) What is the misconception with the second law?
 * 7) Most people believe that keeping motion requires a continued force (this is not true)
 * 8) TRUTH: Newton's laws say a net force (an unbalanced force) causes an acceleration; the acceleration is in the same direction as the net force

__**Homework - Lesson 3 (d) - Newton's Second Law of Motion**__
 * 1) How do you find individual forces?
 * 2) Net Force = Mass * Acceleration
 * 3) Examples of Forces: Tension, Weight, Friction, Normal

__**Homework - Lesson 4 (a-b) - Newton's Third Law of Motion**__
 * 1) What is Newton's Third Law?
 * 2) For every action there is an equal and opposite reaction.
 * 3) Ex. - Flying motion of birds
 * 4) A bird flies by its wings
 * 5) Bird's wings push air downwards while air pushes the bird's wings upwards
 * 6) How do you identify action and reaction forces?
 * 7) Forces always come in pairs
 * 8) Known as "action-reaction force pairs"