CH4_braunsteinc

toc S = Survey (Read the heading of each section and the first sentence of each paragraph. Look at the graphics and pictures to get an idea of what the webpage is about.) Q = Question (Turn the headings into questions to set a purpose for reading, as a prompt for note taking.) R = Read (Read the text to answer your questions and write down the answers in note form.) R = Recite (Cover your answers to the questions and read just the questions, answering them from memory.) R = Review (write a summary of your notes, in paragraph form, or talk it out with your parents (or anyone willing to listen..)
 * Method 4: SQ3R**

=Lesson 1=

lesson 1- a
what is newtons first law? objects continue doing what they're doing (motion wise) unless acted upon by an unbalanced force what are some everyday applications of this law? a cup of coffee filled to the brim in the car will tend to spill when the car starts moving and then again when it stops. when a car stops because of the brakes (which are an unbalanced force when combined with the ground stopping the car) and you keep going b/c theres nothing to stop you.

lesson 1- b
what is inertia? the resistance an object has to change its state of motion what does galileo have to do with it? he developed the concept of inertia, he said that objects stop due to friction why dont forces keep objects moving? forces make objects stop moving, like friction acting on a book sliding across a table. how do you measure inertia? mass is a quantity that is solely dependent on inertia. the more massive, the more inertia.

lesson 1- c
what is a state of motion? state of motion of an object is its velocity (speed and direction) inertia- tendency of an object to change its velocity

lesson 1- d
whats the difference between a balanced and an unbalanced force? balanced: when there are equal and opposite forces acting on an object. ex. a book on a table (weight pulling it down, normal force pushing it up) unbalanced: when there is no other force to balance out a force, like friction. there is nothing to balance out the friction =november 15:=
 * no change in motion unless an unbalanced force acts on the object.... otherwise it will move at constant speed in a straight line**

inertia is a property of matter that measures how difficult it is to change an objects motion. this is mass (not weight)!! weight is a force, pull of gravity on a mass. units of mass- kilograms. units of weight- newtons. weight = mass x gravity

equilibrium: - static- no motion at all, happens when at rest - dynamic- constant speed in either case, the forces are balanced


 * when an unbalanced force acts on an object, it will accelerate in the direction of the unbalanced force**

if normal force is greater than weight force, the object will accelerate up, so the object increases speed up or slows it down going downwards (like diving into a pool).

net force= difference in the unbalanced forces

=Lesson 2=

lesson 2- a
what kinds of forces are there? contact forces- when two objects are physically touching each other. ie. normal, friction, tension action-at-a-distance- when two objects are not physically contacting each other, but still exert a force on each other. ie. gravity

lesson 2- b
what are the different types of forces? whats the difference between sliding and static friction? sliding- when an object slides across a surface static- when two objects are at rest on each other and the other exerts a force on one to set it in motion
 * __ [|Applied Force] __- force applied by a person or another object
 * __ [|Gravitational Force] __- when the earth, moon, planet is so massive that it attracts objects to it
 * __ [|Normal Force] __- force exerted on an object when it is in contact with another stable object
 * __ [|Frictional Force] __- force exerted by a surface when an object moves/ attempts to move across it
 * __ [|Air Resistance Force] __- force that acts on objects as they move through the air
 * __ [|Tension Force] __- force transmitted through a rope, string, chain when it is pulled tight at both ends
 * __ [|Spring Force] __- force exerted by a spring when it is compressed/stretched upon another object

lesson 2- c
what do free body diagrams do? they show relative magnitude and direction on an object

lesson 2- d
how do you figure out the net force on an object? its the difference between the two forces

=Lesson 3=

lesson 3- a
what is newtons second law of motion and what does it mean? it states that the acceleration of an object is dependent on two variables- the net force on the object and its mass. it depends directly on the net force and inversely on the mass.
 * a = Fnet / m **

lesson 3- b
what is the big misconception? many people don't understand or believe what newton's laws mean or dictate. the big misconception is that sustaining motion requires continued force. forces cause acceleration, not motion.

lesson 3- c
how does one find acceleration in a second law problem? if mass and net force are known, this equation is used:

lesson 3- d
how do you determine each individual force? if mass and acceleration are known, use this equation: Fnet = m • a

lesson 3- e
how can newtons second law be used in conjunction with free fall and air resistance? it can be used to answer several questions: why do all objects free fall at the same rate of acceleration regardless of their mass? Is it because they all weigh the same? ... because they all //have the same gravity//? ... because the air resistance is the same for each? Why? Why do objects that encounter air resistance ultimately reach a terminal velocity? In situations in which there is air resistance, why do more massive objects fall faster than less massive objects? by using net force = ma equation, you can determine that the mass is inversely proportional to the force, which offsets the greater force acting on a more massive object. the ratio of the net force to the mass is always the same, around 10, this ratio is called gravitational field strength. the ratio is the same because every object on earth receives 9.8 n of gravity per 1kg. terminal velocity occurs when the force of air resistance is the same as gravity, so the object will continue to fall at a constant speed.

lesson 3- f
=lesson 4=

lesson 4- a
what does newton's third law mean? for every action there is an equal and opposite reaction - forces come in pairs - the size of forces on the first object is equal to the size of the force on the second object - the direction of the force is opposite to the direction of the force on the second object

lesson 4- b
how does one identify an action-reaction pair? - identify the two interacting objects - identify who is pushing whom and in what direction = =

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