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Midterms Flashcards

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1
Q

scientific literacy

A

the set of skills & background knowledge necessary for being a competent scientist

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2
Q

primary goal of science

A

to describe the phenomena that make up the universe (including our world)

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3
Q

physics

A

the study of how the universe works, what the universe is made of, & how the universe is structured

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4
Q

scientific models

A

desc’s of the universe

  • verbal desc’
  • graphs/pics
  • mathematical equations
  • combos of the above
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5
Q

scientific law

A

the pinnacle of scientific desc

description of a phenomenon (relationship among varialbes) thought 2 be universal

usually mathematical

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6
Q

proportional reasoning

A

figuring out how a change in 1/more variables in an equation affects another variable

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7
Q

direct variation

A

when a change in 1 variable produces an equal change in another variable, we say that those 2 variables are “directly proportional”

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8
Q

inverse variation

A

when a change in 1 variable produces a reciprocal change in another variable, we say that they’re “inversely proportional” or that they “vary inversely”

general form L = 1/M

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9
Q

joint variation

A

Equation: c = 5ab

variable c is jointly proportional to a and b. means that c is directly proportional to both a and b

doubling a causes c to double

doubling b causes c to double

doubling bouth a and b causes c to quadruple

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10
Q

What 3 things does a measurement indicate?

A

magnitude

unit

property/quantity being measured

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11
Q

composite/derived property/quantity

A

prop’s/quant’s derived from (made up of) 2/more other quant’s

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12
Q

What kind of units do comp/derived prop’s/quant’s have?

A

composite units

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13
Q

composite units

A

units tht r actually made up of other, more fundamental units

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14
Q

how many fund prop’s r there?

A

7

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15
Q

fund prop’s/quant’s

A

prop’s that can’t be derived from other prop’s

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16
Q

fundamental unit

A

each fund quant has an associated fund unit in the International System(SI System) which is used almost worldwide in science

can’t be broken down in2 other units

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17
Q

fund units of length, time, & mass

A

length - meter m

time - second s

mass - kilogram kg

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18
Q

7 fund units

A

length

time

mass (how much matter)

temperature

electric current

amount (how many of something)

luminous intensity

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19
Q

base unit of mass

A

gram g

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20
Q

order of metric ladder

A

kilo, hecto, deca, base(gram, liter, sec, meter), deci, centi, milli

King Henry Died Monday Drinking Chocolate Milk

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21
Q

can u add measurements with diff properties & units?

A

no, but u can add measurements of diff units & same properties

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22
Q

unit + unit

A

unit

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23
Q

unit - unit

A

unit

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24
Q

unit * unit

A

unit2

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25
Q

can u multiply measurements of diff quantities & units?

A

yes

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26
Q

unita * unitb

A

unita(unitb)

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27
Q

distance

A

so fundamental, it’s diff 2 define w/out reference to distance, length, etc.

the total lenght of the path traveled by an object

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28
Q

time

A

also extremely fund

elapsed time is the duration b/w 2 events

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29
Q

instantaneous speed

A

speed @ a given point in time

the distance traveled divided by the time it took 2 travel that distance

s = d/t

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30
Q

average speed

A

total distance traveled divided by total time it took to travel that distance

the constant speed needed 2 cover the distance of the trip in the time of the trip

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31
Q

motion diagram

A

a series of images of a moving object that records its position after equal time intervals

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32
Q

particle model

A

replaces an object by a single point

size of the obj must be much less than the distance it moves

ignore internal mtions like waving of the arms

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33
Q

origin

A

the pt at which the variables have the value zero

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34
Q

position vector

A

locates the position of the object

lenght of position vector = proportional 2 the distance from the origin 2 the location of the moving obj @ a particular time

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35
Q

scalar quantity

A

a quantity that tells u only the magnitude of something

mass, time, temp, distance, speed

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36
Q

vector quantity

A

tells not only the magnitude of something, but also its direction

velocity, acceleration, position, force

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37
Q

displacement vector

A

drawn from the position of the moving @ an earlier time 2 its position @ a later time

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38
Q

time interval

A

>t = t1 - 10

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39
Q

average velocity

A

v = >d/>t

increases when d increases & t decreases

on PT graph, same as slope

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40
Q

instantaneous velocity

A

the speed and direction of an obj @ a particular instant in time

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41
Q

displacement

A

>x = d1 - d0

a change in position

d is always greater than/equal to |>x|

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42
Q

average acceleration

A

an object in motion whose velocity is changing is said to be accelerating

a = >v/>t

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43
Q

position

A

d1 = d0 + vt

location in space relative 2 a reference pt

includes distance & direction

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44
Q

mechanics

A

branch of physics concerned w/ motion

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45
Q

kinematics

A

branch of mechanics tht describes motion w/out considering the causes of motion

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46
Q

motion

A

a change in location/position of an obj over time

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47
Q

velocity & acceleration relationship

A

v a

increase speed

+ +

  • -

decrease speed

+ -

  • +
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48
Q

direction of motion & no motion (“at rest”) on VT graph

A
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49
Q

what regions indicate “slow” and what regions indicate “fast” on a VT graph

A
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50
Q

constant acceleration in pos. & neg. directions in VT graphs

A
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51
Q

constant deceleration in pos & neg directions on VT graph

A
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52
Q

equations to know

A

v = >d/>t

a = >v/>t

df = di + vt OR >x = vt

vf = vi + at OR >v = at

>x = 1/2 (vi + vf) t OR df = di + 1/2 (vi + vf) t

>x = vi • t + 1/2at2 OR df = di + vi t + 1/2at2

vf2 = vi2 + 2ax

ht(down/up) = [2x/a

ht(down & up) = 2[2x/a

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53
Q

free fall

A

when an object falls under the ifnluence of gravity alone

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54
Q

gEarth = ?

A

-9.81 m/s2

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55
Q

what lesson did scientists have to relearn?

A

our perception of motion can be influenced by how we observe it

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56
Q

acceleration

A

how velocity changes over time

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57
Q

explain or demonstrate why the unit for accel is m/s2

A

the units are m/s2 because acceleration is the change in velocity over time/per unit time. velocity has fundamental units of m/s and time has fundamental units of s, so acceleration = change in velocity/change in time yields units of m/s/s. this yields m/s2 as shown below: m/s/s = m/s • 1/2 = m/s2

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58
Q

celestial bodies

A

refer to those things we see beyond the earth, in the “heavens”

moon, sun, planets

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59
Q

what do some of humankind’s earliest recorded observations of motion concern?

A

cycles of sun, moon, stars

Ex: daily cycle of sun, 28 day cycle of moon, nightly & seasonal cycle of stars

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60
Q

instead of sci analysis, how were the movements of celestial objects explained?

A

based on religious ideas/primitive analogies w/ the kind of motions they observed around themselves

Ex: Greeks thought the Sun was a god who rose out of the ocean and drove a chariot across the sky

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61
Q

when were the 1st telescopes invented?

A

17th century (1600’s)

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62
Q

what were the early Greeks responsible for? when?

A

began developing systems of thought tht explained phenomena according to empirical/logical principles vs. religious ideas

5th & 6th centuries BC

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63
Q

2 early Greek philosphers

A

Thales of Miletus & Pythagoras

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64
Q

who developed the Greek understanding of motion? when?

A

Aristotle

384-322 BC Athens

65
Q

for how long did the Greek understanding of motion dominate European thought abt motion?

A

more than 1,000 years

66
Q

Aristotle’s understanding of motion

A
  1. All objects have a tendency to move toward their “natural” place, depending on what they’re made of (earth, water, air, fire)
  2. The Earth is @ the center of the universe & doesn’t move
  3. Sun, Moon, & planets moved in perf circles around earth (constant distance, speed, & direction)
  4. speed of obj’s to/from earth depended on weight
  5. any obj set in motion, on the earth & @ any rate, will eventually slow & stop. force necessary to keep it moving
67
Q

on what was Aristotle’s understanding of motion based?

A

observations

logic & empirical principles

68
Q

problems w/ Aristotle’s ideas

A

w/ observation, obvious tht the planets were sometimes closer 2 Earth than @ other times & tht they moved in their orbits @ varying speeds

69
Q

how did Ptolemy try to make the observations of celestial motion fit Aristotle’s theory/explanation of motion

A

epicycles

said the planets also revolving in mini orbits

70
Q

what did epicycles explain?

A

retrogade motion

planets appeared to move backwards sometimes

71
Q

benefits of Ptolemaic system

A

explained curious motions of the planets

allowed for the prediction of the future positions

72
Q

role of the Catholic church in promoting Ptolemy’s & Aristotle’s understanding of the structure of the universe

A

regarded by Church as “authorities” who, tho they lived in the pre-Christian era, had put forward doctrines tht contained divine wisdom

scholars who questioned these authorities might have publications of their books prohibited, or even been imprisoned/executed

73
Q

why were philosophers, scientists, & Christian scholars disturbed by Ptolemy’s system (geocentric w/ planets orbiting on 1/more epicycles)

A

made the system jury-rigged, like a clunky machine fitted out w/ additional parts just to make it work properly

lacked the elegance & simplicity tht even the Christian scholars thought God’s work should reveal

74
Q

who was William of Ockham

when was he alive

what was his important philosophical & scientific principle

A

Franciscan monk & Oxford scholar

1285-1349

“entities must not be needlessly multiplied”

75
Q

Ockham’s/Occam’s Razor

A

when considering competing explanations, 1 chooses the simplest explanation (the one w/ the fewest assumptions) & is supported by evidence

when considering an explanation, u should suspect tht it’s false if it needs assumption/extra parts added to it over time to fit new data

76
Q

what was Copernicus’ insight into the problem of retrograde motion & the reason y the Ptolemaic system was failing to accurately predict planetary positions

A

retrograde movement of Mars occurs cuz it has a larger orbit than earth, so earth sometimes passes it, making it look like it’s going backwards

from view of observer

77
Q

what aspects of ptolemy/aristotle’s system did copernicus retain in his heliocentric system?

A

didn’t challenge the other Ptolemaic ideas of how planets moved @ constant speeds & in perf. circles

to explain, had to retain some of the epicycles

78
Q

what did Kepler (1571-1630) realize abt the orbits of the planets around the sun?

A

the planets moved in elliptical, not circular, orbits

the planets moved faster the closer they were to the Sun & slower the farther away cuz Sun exerted some sort of force

79
Q

effect of Kepler’s Laws of Planetary Motion

A

had provided the mathematical foundation for the acceptance of the Copernican theory of the solar system

now positions & movements of the planets could be calculated w/ a high degree of accuracy

80
Q

why did the heliocentric view seem absurd to some ppl?

A

if earth was indeed moving thru space @ incredible speeds & spinning on an axis, y don’t we feel the motion/fall off?

81
Q

what did Galileo demand of his students?

A

that they test their ideas thru experimentation & empirical observation

82
Q

Galileo’s procedure for testing Aristotle’s ideas of motion?

A

used his pule (& other mechanisms such as water clocks) as a timer, and rolled objects of diff weights down inclined planes

83
Q

what did Galileo find in testing Aristotle’s ideas abt motion?

A
  1. all obj’s near surface of the earth fall @ same rate of accel, regardless of weight
  2. force not required 4 motion. force doesn’t cause motion –> changes in motion
84
Q

what argument did Galileo use to defend heliocentric view?

A

sailors on a ship can’t feel ship’s motion when moving @ constant speed on calm sea

85
Q

in which book did Galileo put forth his argument?

A

Dialogue on the Two Chief World Systems, 1632

86
Q

who was born same year galileo died

A

Isaac Newton (1642-1727)

87
Q

galileo’s law of falling bodes

A

cumulative distance fallen is proportional to the square of time, and the distance fallen b/w each successive time interval increases according to the progression of odd #’s

88
Q

contributions of Galileo

A
  1. all obj’s near surface of earth fall @ same rate of accel regardless of weight
  2. after initial impluse, an obj might move forever until opposed by another force (inertia)
  3. total distance fallen is proportional to t2
  4. the distance fallen b/w each successive time interval increases according to the progression of odd #’s
  5. telescope
  6. movement & surfaces of celestial bodies
  7. precise measurements to test ideas
89
Q

force

A

a push/pull on an object

transferred from one object to another

causes change (direction/speed) in motion - does not cause motion

not necessary to sustain motion

vector quantity

90
Q

inertia

A

responsiveness to force

no object(or their mass) can resist a force - only other forces can counter a force

indicated by mass: as mass goes up, inertia goes up, and acceleration responsivess goes down

if an obj is at rest, it tends to remain at rest. if it is moving at a constant velocity, it tends to continue moving at that velocity

91
Q

Newton’s 2nd Law

A

f = ma

92
Q

unit of force

A

Newton(N)

93
Q

what equation can be derived from Newton’s 2nd law?

A

a = fnet/mass

94
Q

2D vector adding

A
  • put arrows head to tail MAKE SURE U DON’T CHANGE THEIR DIRECTION
  • if @ right angles, Pythogorean Theorem
  • if not right angle:
  • form a parallelogram & then the diagonal coming from b/w the 2 vectors will be the resultant
  • can also split bottom vector into horizontal & vertical components & join them w/ top vector, + the parallel vectors, put the remaining vectors back together @ right angle, & then use Pythogorean Theorem
95
Q

if 3 motorboats crossing a river & motorboat a’s resultant is straight across, b’s is closest to opposite shore, and c’s is longest, then

a) which boat reaches the opp shore first?
b) which boat provides the fastest ride?
c) which boat takes the shortest path to the opp shore?

A

b

c

a

96
Q

how to tell speed of resultant

A

length

97
Q

weight

A

strength of the force of gravity on an obj

unit of measure = N/lbs

measured by spring scale

W = mg; W = mass•accel(from gravity)

depends on laction in a gravitational field

98
Q

mass

A

measure of the amount of matter in an object

indicates inertia

measured by a balance

fundamental

unit = kg

would not differ on moon and Earth

mass = energy

99
Q

how r weight & mass related

A

directly proportional

100
Q

how r force & accel related?

A

directly

101
Q

how r mass & acceleration related?

A

inverse relationship

102
Q

when doing pulley & cart experiment, how do u calculate the acceleration?

A

force is the weight attached to the end of the pulley

mass is the mass of the weights @ end of pulley + mass of cart + any masses on cart

103
Q

what r the fund units that make up a Newton (N)?

A

kg•m

_____

s2

104
Q

net force

A

the vector sum of all forces acting on an object

something that disturbs the state of equilibrium/changes the velocity of an object

105
Q

contact force

A

acts on an obj only by touching it

Ex: friction

106
Q

long-range force

A

exerted w/out contact

Ex: weight

107
Q

Friction (Ff)

A

the contact force that acts to oppose sliding motion b/w surfaces

parallel to surface & opp. direction of sliding

108
Q

Normal (FN)

A

the contact force exerted by a surface on an obj

perp to & away from the surface

109
Q

Spring (Fsp)

A

a restoring force, the push/pull a spring exerts on an obj

opp. the displacement of the obj @ the end of the spring

110
Q

Tension (FT)

A

the pull exerted by a string, rope, or cable when attached to a body & pulled taut

away from the obj & parallel to the string, rope, or cable @ the pt of attachment

111
Q

thrust (Fthrust)

A

a general term for the forces that move objects such as rockets, planes, cars, & ppl

in the same direction as the accel. of the obj barring any resistive forces

112
Q

Weight (Fg)

A

a long-range force due to gravitational attractin b/w 2 obj’s, generally Earth & an object

straight down toward the center of the Earth

force of weight = force of gravity

113
Q

common misconceptions

A
  • when a ball has been thrown, the force of the hand tht threw it DOES NOT remain on it - it is a contact force & thrfore once contact is broken, the force is no longer exerted
  • a force is NOT needed to keep an obj moving - if there’s no net force, then the obj keeps moving w/ unchanged velocity. if friction is a factor, then there’s a net force & the obj’s velocity will change
  • inertia is NOT a force - forces r exerted on obj’s by the environ, they r not properties of obj’s
  • air DOES exert a force (a huge force), but cuz it is balanced on all sides, usually exerts no net force unless an obj is moving
  • the quantity ma is NOT force - the equals sign in F=ma doesn’t define ma as a force; rather, means that experiments have shown tht the 2 sides of the equation r equal
114
Q

a ball is thrown straight up into the air

@ the very top of its trajectory of motion(just before it starts to fall back down) the net force on the ball is?

A

its weight

at the top, the only force acting on the ball is the force of gravity(same as weight)

115
Q

how to calculate what friction force acts on a mass

A

Ex: A horizontal force of 5.0N accelerates a 4.0-kg mass, from rest, at a rate of 0.50m/s2 in the positive direction. what friction force acts on the mass?

  1. calculate normal force. F = ma → F = 4kg•0.5m/s2 = 2N
  2. Find the net force b/w 2N from previous step & given force (5N)
  3. 5N - 2N = 3N
116
Q

equlibrium

A

an obj is in equilibrium if it’s @ rest or if it’s moving @ a constant velocity

net force = 0

117
Q

Newton’s 1st Law of Motion

Law of Inertia

A

Any obj will remain @ rest/moving w/ uniform motion (constant speed AND constant direction) iff the net force acting on tht obj is zero.

OR

a net force acting on an obj will cause tht obj to accel (change its motion by changing its speed and/or direction)

a = f/m → responsiveness to force = net force/inertia

118
Q

inertia

A

responsiveness of an obj to force

119
Q

inertia & mass

A

the measure of an obj’s inertia is the obj’s mass

the more mass an obj has, the more inertia it has, & the less it responds to force

120
Q

canceling a force

A

only a force can resist/cancel another force. mass(inertia) by itself can NOT resist force

when an obj appears to resist a force cuz it doesn’t accel in response 2 the force, always cuz another force is acting. usually friction

121
Q

Greek philosopher Aristotle asserted that

A

force is required for motion

heavier obj’s fall faster than lighter obj’s

122
Q

accel of an obj is due to

A

an unbalanced force acting on the obj

123
Q

an obj following a straight-line path at a constant velocity must

A

have zero acel

still forces acting, just canceled out

124
Q

on a VT graph, what tells u the instantaneous acceleration at any time?

A

slope

125
Q

decreasing positive velocity on PT graph

A
126
Q

decreasing neg velocity PT graph

A
127
Q

increasing pos velocity PT graph

A
128
Q

increasing neg velocity PT graph

A
129
Q

on a VT graph, what tells you the displacement that occurred during the motion?

A

the area under the graph

130
Q

relationship b/w accel & mass in newton’s 2nd law

A

inverse

131
Q

relationship b/w accel & force in newton’s 2nd law

A

direct

132
Q

you r sitting in the back seat of a car that is moving at a constant speed in a straight line. u hold a baseball directly above ur lap & drop it. the ball lands

A

in ur lap

cuz CONSTANT VELOCITY

133
Q

u’re sitting in the back seat of a car that is moving @ a constant speed in a straight line. you hold a baseball directly above ur lap & drop it. just as u drop it, the driver of the car hits the brakes hard. the ball lands

A

ahead of ur lap

VELOCITY CHANGED

134
Q

passenger in car moving in straight line @ constant speed

car turns sharply to left & u’re thrown against side door

A

when a passenger is wearing a seatbelt, basically share the same state of motion as the car. accelerate & decelerate w/ the car(except for internal organs & head)

when not wearing seat belt, separate obj’s w/ separate rates of motion. when the car abruptly changes direction, the passenger continues w/ the same velocity as before (until they hit the door)

135
Q

Newton’s 3rd Law of Motion

A

for every force thr is an equal & opp reaction force

FAonB = -FBonA

136
Q

action-reaction pair

A

the 2 forces involved

do not cancel each other out

137
Q

“equal”

A

equal in magnitude

simultaneous - occur @ exactly same time & last for same amount of time

138
Q

“opposite”

A

opposite in direction

180o

139
Q

y don’t action & reaction forces cancel each other out?

A

they r usually acting on diff obj’s

140
Q

where do u draw vectors?

A

on the obj receiving the force

141
Q

Why does Bob beat Annie in tug of war?

A

based on newton’s 3rd law, they r both exerting the same amount of force, but Bob still wins cuz he is exerting more force on the ground

142
Q

if the floor is exerting a reaction force back on u due to ur weight on it, then y don’t u get pushed into the air away from the floor?

A

gravity pushes u down

143
Q

if a horse exerts a force on the cart & the cart exerts an equal but opp force on the horse, how can the horse move the cart?

A

more than just the 2 forces acting on them

also, the 2 forces r both acting on diff obj’s w/ diff masses

144
Q

when can action-reaction forces cancel each other out?

A

if they r part of the same system & become internal forces

145
Q

drawing tug of war vectors

A

rope on gm -> rope on gp <-

Earth on gm v gm on earth ^

Earth on gp v gp on Earth ^

gm on ground -> ground on gm <-

gp on ground <- ground on gp ->

gm on rope <- gp on rope ->

ground on gm ^ gm on ground v

ground on gp ^ gp on ground v

146
Q

Work

A

exerting a force over a distance

when u exert a constant force on an object thru a distance, in the direction of the force, u do an amount of Work on the object

W = f•d

W is positive, & the energy of the obj increases by an amount equal to W

neg. work is done when exerting a force on an obj in the direction opposite to its motion

W = change in energy; work done on an obj + energy, an obj doing work - energy

147
Q

kinetic energy

A

energy of motion

final KE = initial KE + W

K = 1/2mv2

Joules

148
Q

gravitational potentional energy

A

GPE

if system b/w an obj & Earth, gravitational attraction b/w them = an interaction force. if obj moves away from Earth, energy = stored in the system as GPE as a result of the gravitational interaction b/w the obj & the Earth.

Ug = mgh

149
Q

reference level

A

where the GPE is defined to be 0

random

150
Q

energy

A

the ability to do work

amount of energy = amount of work possible

151
Q

Joules

A

kg • m2

_______

s2

simpifies to F•d

152
Q

force → energy

A

forces r responsible for changing energy from 1 form to another

they move energy from 1 obj to another as well

153
Q

potentional energy

A

stored energy

often has to do with resisting some kind of force

154
Q

energy equations

A

all come form F • d

155
Q

Law of Conservation of Energy

A

as long as the system under investigation is closed so that the objects don’t move in & out, & as long as the system is isolated from external forces, then energy can only change from or be transferred

Kbefore + Ugbefore = Kafter + Ugafter

156
Q

mechanical energy

A

E = KE + Ug

only if no other forms of energy r present

157
Q

relationship b/w mass & energy

A

mass = energy

E = mc2

158
Q

power

A

rate @ which energy is transferred/transformed

p = >E/>t

unit = Watt (W) = J/s = (kg•m2)/s2

                                   \_\_\_\_\_\_\_\_\_\_\_    = (kg•m<sup>2</sup>)/s<sup>3</sup>

                                            s

Intro to Physics (8 decks)

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