Scientific Concepts Chapter 2

Front 1

Motion (describing)

Back 1

-3 basic concepts: position, speed and velocity, acceleration
-applications: horizontal motion on land, falling objects, compound (2-D) motion

Front 2

Motion (explaining)

Back 2

-Basic ideas: forced, inertia and mass, Newton's laws
-Applications: momentum and impulse, circular motion, Newton's law of gravitation, earth satellites

Front 3

Motion (measuring)

Back 3

-two fundamental components: change in position, change in time
-3 important combinations of length and time: speed, velocity, acceleration

Front 4

Speed

Back 4

speed= distance/time
-change in position with respect to time
-average speed= most common measurement
-instantaneous speed= time interval approached zero

Front 5

Velocity

Back 5

-described speed (how fast is it going?) and direction (where is it going?)
-graphical representation of vectors: length=magnitude; arrowheads=direction

Front 6

Acceleration

Back 6

-rate at which motion changes over time
-speed can change
-direction can change
-both speed and direction can change
-can be negative

Front 7

Uniform Acceleration

Back 7

-constant, straight-line acceleration
-average velocity simply related to initial and final velocities in this case

Front 8

Force

Back 8

-a push or pull capable of changing an objects state of motion
-overall effect determined by the (vector) sum of all forces- the "net force" on the object

Front 9

Gravitational Force

Back 9

-mass interactions
-motions of planets, stars, galaxies

Front 10

Electromagnetic Force

Back 10

-charge interactions
-electricity and magnetism
-atoms and molecules, chemistry

Front 11

Weak Force

Back 11

-involved in certain nuclear reactions

Front 12

Strong Force

Back 12

-holds nuclei together

Front 13

Inertia

Back 13

measure of an objects tendency to resist changes in its motion (including rest)

Front 14

Balanced and Unbalanced Forces

Back 14

-motion continues unchanged without unbalanced forces
-retarding force decreases speed
-sideways force changes direction

Front 15

Free Fall

Back 15

falling under influence of gravity w/o air resistance

Front 16

Falling Objects

Back 16

-distance proportional to time squared
-speed increases linearly with time
-trajectories exhibit up/down symmetries
-acceleration same for all objects

Front 17

Compound Motion

Back 17

-3 types of motion: vertical motion, horizontal motion, combo of 1 and 2
-projectile motion: an object thrown into the air
-basic observations: gravity acts at all times; acceleration (g) is independent of the object's motion

Front 18

Projectile Motion (vertical projectile)

Back 18

-slows going up
-stops at top
-accelerates downward
-force of gravity acts downward throughout

Front 19

Projectile Motion (horizontal projectile)

Back 19

-horizontal velocity remains the same (neglecting air resistance)
-taken with vertical motion=curved path

Front 20

Fired Horizontally vs. Dropped

Back 20

-vertical motions occur in parallel
-arrow has an additional horizontal motion component
-they strike the ground at the same time

Front 21

Newton's 1st Law of Motion

Back 21

-"the law of inertia"
-every object retains its state of rest or its state of uniform straight-ling motion unless acted upon by an unbalanced force
-inertia resists any changes in motion

Front 22

Newtons 2nd Law of Motion

Back 22

-forces cause accelerations
-units= Newtons (N)
-proportionally constant =mass
-more force, more acceleration
-more mass, more acceleration

Front 23

Mass

Back 23

-quantitative measure of inertia
-the amount of matter

Front 24

Weight

Back 24

force of gravity acting on the mass

Front 25

Kilogram

Back 25

measure of mass

Front 26

Momentum

Back 26

-important property closely related to Newton's 2nd law
-includes effects of both motion (velocity) and inertia (mass)

Front 27

Conservation of Momentum

Back 27

-total momentum of a group of interacting objects remains the same in the absence of external forces
-applications: collisions, analyzing action/reaction interactions

Front 28

Impulse

Back 28

-a force on an object for some time (t)
-an impulse produces a change in momentum
-applications: airbags, padding for elbows and knees, protective plastic barrels on highways

Front 29

Newton's Law of Gravitation

Back 29

-attractive force between all masses
-proportional to product of the masses
-inversely proportional to separation distance squared
-explains why g=9.8 m/s2
-provides centripetal force for orbital motion