a discipline of focused study that is systematic, comprehensive, and addresses specific questions

-collective findings of humans about nature, and a process of gathering and organizing knowledge about nature

data based/driven

test explanation based on data

ALL the data, not choosing some data and not other

-look at the same data

data does not depend on the observer

logical connection between data explanation

-math

1. nature (material world) understandable

2. nature is uniform (in time and space) data only implies to that place and time

3. observable patterns in nature provide clues to understand unobservable patterns

2 types

1. natural motion: moves on its own/moves with nature. i.e. rock falls down)

2. forced motion: throw rock up

everything composed to 4 elements: fire, air, water, earth

the distance traveled per time

speed= distance covered/travel time

net force=zero

every object continues in a state of rest or unified speed in a straight line unless acted on by a nonzero force

an object is going to move in a straight line unless acted upon by another force greater than zero

acceleration≈ net force/mass

the acceleration produced by a net force on an object is directly proportional to the net force, is in the same direction as the net force and is inversely proportional to the mass of the object

acceleration depends the force acted upon the object as well as the mass of the object

whenever one object exerts a force on a second object, the second object exerts an equal and opposite force on the first

when 2 objects collide they exert an equal yet opposite reaction

falling only under the influence of gravity--falling without air resistance 

acceleration= change in speed/time interval

10 m/s ÷ 1s=10 m/s²

a push or a pull

needed to start moving an object

in the absence of an external force, the momentum of a system remains unchanged. 

mv_{(before event)}=mv_{(after event)}

Ft=Δ(mv)

change in momentum 

1. increasing momentum:apply the greatest force possible for as long as possible

2. decresing momentum over a long time:extend the time during which your momentum is brought to zero

3. decreasing momentum over a short time:short impact times=larger impact forces

when objects collide

1. elastic: conservative (bounces back)

2. inelastic:nonconservative (sticks)

net momentum_{(before collision)}=net momentum(after collision)

whenever objects collide in the absence of external forcesthe net momentum of both objects before the collision equals the net momentum of both objects after the collisions

energy: the ability to DO WORK!

work: how much force you put on an object and how long 

force x distance=work

KE=½mass x speed²

energy of motion

resting energy

it is stored and held in readiness

equal to the amount of work done per time it takes to do it

power= work done/time interval

the work output of any machine cannot exceed the work imput. 

work_input=work_output

(Fd)_input=(Fd)_output

every body in the universe attracts every other body with a force that, for two bodies, is directly proportional to the square of the of the distance separating them

F=G(m₁m₂/d²)

fifth element, perfect

motion-perfect circle

fire, water, water, earth

four elements

the intensity of an effect from a localized source spreads uniformly throughout the surrounding space and weakens the inverse square of the distance

intensity= 1/distance²

neap tides: waxing 1/2 moon and waning 1/2 moon

spring tides: when moon, earth, and sun are lined up; new and full moon

-quantities have 2 parts, size and direction 

-velocity, acceleration, & force are all vectors

-quantities that only have size are referred to as scalar

-add in geometric fashion to yield the resultant

1. each planet moves in eliptical orbits with the sun at one focus

2. the line from the planet to the sun sweeps out equal areas in equal time;a planet moves faster when it is closer to the sun and slower when it is further away.

3.The square of the orbital period (T²) is proportional to cube of the average distance form the sun (R³) [ T² ~ R³ ] a planet that orbits with a large radius moves much slower than a planet with a smaller orbital radius.