GALILEO: Since he experimented to get _________ for his conclusions, he is considered to be the father of ____________ physics.

Things in motion tend to ___________________; they do NOT tend to ____________________ ON THEIR OWN. In fact, Galileo figured out that it TAKES ___________ to make something slow down or stop. The usual force is (he discovered): ________________.

So in fact, GALILEO figured out the principle behind what we call __________________

NEWTON’S 1 ST LAW An object at rest tends to stay at rest, and an object in motion tends to stay in motion in a ______________ at _____________ unless acted on by an outside _______ force.

INERTIA refers to Newton’s 1 st Law Inertia is a measure of an object’s _______________ to _____________ in state of motion. The word inertia comes from the Italian word for “_________________.” Inertia is ________________PROPORTIONAL TO ___________ ONLY. INERTIA IS NOT _____________ !!! IT IS A ___________________________!

What is the difference between mass and weight? WEIGHT is –the pull due to __________. –Weight CHANGES due to location! –Weight is a ___________! –It is a vector. MASS is the amount of _____________ in an object.the amount of _____________ in an object. Mass does NOT ___________, regardless of location.Mass does NOT ___________, regardless of location. Mass is measured in kg.Mass is measured in kg. It is a scalar.It is a scalar.

inertia… If you are floating around in space outside the space shuttle, and go up to it and give it a kick, what will be the results?

What is force? A _________________. A _____ force is the leftover (or unbalanced) amount of force after you add up all the forces acting in a certain direction. (examples in a sec…) Only NET forces cause ______________________! No net force means ____________.

Newton’s 2 nd Law: The acceleration of a body is directly proportional to the ___ _____ on it, and inversely proportional to the _____. This means F net = ma, but is usually just written _________

FORCE UNITS Think of Newton’s 2 nd law: F = m a N = kg m/s 2 Since mass is in kg, and a is in m/s/s, or m/s 2, F or Forces are measured in kg m/s 2. That is the SAME as a Newton, or N.

F = ma 100N = 100kg X 1.00m/s 2 a = F/m 1.00m/s 2 = 100N / 100kg

…Newton’s 2 nd Law… This makes sense…the more massive something is, the ________ it is to accelerate. And the more force there is, the _______ something will accelerate. Zero net force means _______ acceleration.

F = ma W = mg A 2 kg mass accelerating at 3 m/s 2 has how much net force on it? If you weigh 150 pounds, your mass is about 68 kg. (1 kg = 2.2 lbs.) What is your WEIGHT in Newtons here on Earth?

SOLUTIONS A 2 kg mass accelerating at 3 m/s 2 has how much net force on it? ___________________________ If you weigh 150 pounds, your mass is about 68 kg. (1 kg = 2.2 lbs.) What is your WEIGHT in Newtons here on Earth? ____________________________

F = ma a = F/m A force of 16 N is pulling on a 2 kg wagon. If there is no friction, how fast is the wagon accelerating? If the wagon above is going at a CONSTANT VELOCITY with the 16N pull, how much friction is there?

A force of 16 N is pulling on a 2 kg wagon. If there is no friction, how fast is the wagon accelerating? _____________________________ If the wagon above is going at a CONSTANT VELOCITY with the 16N pull, how much friction is there? _______________ ! If going constant velocity, acceleration is _______, & net force is ________ so all forces are BALANCED (equal) in any 1 direction.

Newton’s 3 rd Law: Every action [force] has an equal and ________ reaction [force]. There are NO single ______________. They always occur as an ___________pair.”

For example, you touch the table with 1N of Force, it touches you back with 1N of Force ____________________ (not a little later!).

Newton’s 3 rd Law says that an action reaction pair would be hands pushing on barbell, barbell pushing on hands. Then HOW can the barbell be ACCELERATED upward? What OTHER action reaction pairs are involved?

More on Newton’s 3 rd … If you smash the wall with your fist with 80 N of force, the wall will hit you right back with 80 N. But what if you hold a piece of paper in the air and try to hit it with 80 N?

If the paper … cannot support or hit you back with 80 N, can YOU really hit IT with 80 N? If the paper can only hit you back with 5 N, what happens to the other 75 N from your punch??! HINT:

Force of friction Opposes ____________ Occurs between _____________ in contact

FOUR TYPES OF FORCES Right now we think there are 4 different types of forces. Einstein was working on a “unified force theory” before he died, and others continue that work today, believing that there is really only one type of force.

The four types of forces (weakest to strongest) are: 1.Gravitational 2.Weak [Nuclear] 3.Electromagnetic 4.Strong [Nuclear]

Gravitational force… Is the ____________ of all the forces, but acts over the ____________ distances! You are pulling and pulled by _____ __________ IN THE __________!!!

___________ forces… Are the forces that act due to electron configuration in atoms These forces are responsible for the ________________ or characteristics of elements, compounds, and materials

This force makes paint stick to a wall, makes diamonds extremely hard, makes gold malleable, rubber stretchy, water a bipolar molecule, etc.