definations Flashcards
1
Q
what is scalar quantity
A
-has magnitude (size)
2
Q
what is vector quantity
A
-has magnitude (size) and direction
3
Q
define velocity
A
speed with a given direction
4
Q
define speed
A
distance covered in a given time
5
Q
define acceleration
A
change in velocity per unit time
6
Q
what do you call negative acceleration
A
deceleration
7
Q
define displacement
A
Object/s overall change in position (how far from start to end)
8
Q
define distance
A
how far an object moves (how much travelled)
9
Q
define mass
A
amount of matter in an ogject
10
Q
define gravitational field strength
A
gravitational force per unit mass
11
Q
define weight
A
gravitational force acting on an object with mass
12
Q
define density
A
amount of mass in a given volume
13
Q
define analogue device
A
a measuring device that users have to read from a scale
14
Q
define an digital device
A
a measuring device that displays the measurement instead of user reading it from a scale
15
Q
define a pendulum
A
a weight suspended from a pivot so that it can swing freely
16
Q
define freefall
A
motion under the force of gravity alone
17
Q
define liner motion
A
motion where acceleration is not constant
18
Q
define uniform motion
A
motion where acceleration is constant
19
Q
define terminal velocity
A
steady speed of an object freely falling through a gas or liquid
20
Q
Define force
A
a push , pull or a twist
21
Q
define friction
A
force that opposes one surface moving or tying to move past another (opposes motion)
22
Q
define static friction
A
force that keeps an object at rest
23
Q
define dynamic friction
A
opposes sliding or rolling motion
24
Q
what is resisting force
A
force opposing another force
25
What is resultant force
a single force that can replace all individual forces acting on the object, and have the same effect
26
define Newton's 1 law
An object will remain stationery ( at rest) or move in a constant (uniform) speed in a straight line unless a net resultant force acts on it
27
define Newton's 2 law
force = mass x acceleration
F = ma
28
define Newton's 3 law
for every action, there is an equal and opposite force on it (forces act in pairs)
29
define Inertia
an objects resistance to change in speed and direction
30
define mass of body in inertia
a measure of inertia
31
Define balanced
forces in opposite directions that have the same magnitude
32
define human reaction time
time taken for a human reaction
33
define elastic object
an object that returns back to its original shape
34
Define limit of proportionality
-the point beyond which the extension of an elastic object is no longer directly proportional to the force applied to it
-(where it stop being proportional)
35
What is Hooke's law
the extension of a spring is directly proportional to the force applied to it until it exceeds the limit of proportionality
36
define spring constant (k)
stiffness of spring
37
define spring extension (x)
extension of spring
38
define moment
turning force
39
define Equilibrium in a moment
the clockwise and anti-clockwise moments are equal (balanced) = resultant force and moment are 0
40
define pivot
turning point (need to touch the surface)
41
Define centre of gravity
point where the whole weight of an object seems to act
42
Define distance in moment
distance has to be perpendicular to pivot from the force
43
define a regular shape
has 1 or more lines of symmetry
44
define stability
how likely an object will fall when disturbed
45
define stable equilibrium
-object returns to its original equilibrium position
46
Define unstable equilibrium
-object does not return to its original equilibrium position
47
define Neutral equilibrium
-object remains in displaced position
48
what is pressure
force over area
49
define mechanical work done energy transfer
applied force
50
define electrical work done energy transfer
difference in charge causing electrical charges to move
51
define heat energy transfer
difference in temperature
52
define waves energy transfer
wave is transferred as radiation
53
define law of conservation of energy
energy cannot be created or destroyed
54
define law of conservation of mass
mass cannot be created or destroyed
55
define work done
transfer of energy by electrical or mechanical pathways
56
define power
how much energy / work done over time
57
define accurate
how close measurement is to the true/ accepted value
58
define precise
how close measurement of the same value are to each other
59
define reliability
how small the variations btw values are
60
Define nuclear fission
nuclei of atoms split apart
61
define renewable source of energy
energy that is made faster than used
62
define non-renewable source of energy
energy that is being used faster than it is made (unsustainable)
63
define melting
change of state of matter from solid to liquid
64
define boiling/ evaporation
change of state of matter from liquid to gas
65
define condensation
change of state of matter from gas to liquid
66
define freezing
change of state of matter from liquid to solid
67
define sublimation
change of state of matter from solid to gas
68
define depostion
change of state of matter from gas to solid
69
define heat
amount of thermal energy
70
define lattice
regular repeated arrangement of atoms
71
define temperature
average kinetic energy of particles
72
define Brownian's motion
zig- zag motion of particles when suspended in fluid as a result of collision of particles in fluid.
73
what is pressure in container
force of particles colliding on the wall of the container
74
define expansion
particles gain thermal energy which is converted into kinetic energy to intermolecular forces and move apart
75
define absolute 0
-when particles have no kinetic energy = no movement
-measured in kelvin
76
define cold
absence of heat
77
what is 0K in C
0K = -273 C
78
define conduction
transfer of energy through collision of particles
79
define humidity
amount of water vapour in air
80
define insulators
poor conductors of heat eg. air, wood, plastic
81
define good conductors
conducts heat/ electricity easily
82
define convection
transfer of energy in fluids by creating a convection current where less dense hot particles rises and more dense colder particles sinks
83
define fluids
liquid or gas
84
define vacuum
no particles
85
define radiation
transfer of energy by a wave
86
define emission
release / give out
87
define transmission
traveling through a medium
88
define global warming
-average temperature of the earth increasing
89
define climate change
-long term changes of climate
90
define the greenhouse effect
the earth's atmosphere traps heat
91
define longitudinal wave
wave which oscillations are parallel to direction of wave motion/ energy transfer
92
define transverse wave
wave which oscillations are perpendicular to direction of wave motion/ energy transfer
93
define compression
region with most pressure in longitudinal wave
94
define rarefaction
region with least pressure in longitudinal wave
95
define amplitude
max distance between the peak/ trough and position of equilibrium
96
define equilibrium
position where displacement is 0
97
define wave length
-distance btw 2 adjacent peak & trough/ compression & rarefaction
98
define a wave
-disturbance that transfers of energy without transferring matter away form source
99
define peak / crest
highest point of a transverse wave
100
define trough
lowest point of a transverse wave
101
define period
time taken for 1 wave length
102
define frequency
number of wave lengths per second
103
define oscillations
-max displacement of a wave
(vibrations)
104
what is λ
-lambda
-wave length
105
define wave speed
speed which wave travels in
106
define refraction
-change in direction of wave as they pass through different mediums
107
define reflection
-wave bounces off a plane surface
108
define electromagnetic waves
waves with vibrations btw electric and magnetic field
109
define diffraction
-bending at the ends of a wave as it passes through a narrow gap
110
define plane surface
2D flat surface
111
define echoes
reflected sound
112
define an oscilloscope
apparatus that converts longitudinal waves to transverse waves
113
define rule of incidence for reflection
angle of incidence = angle or reflection
114
define normal
perpendicular line from the surface
115
define wave front
-set of all locations in a medium where the wave is at the same place
imaginary surface that represent the points in a wave that vibrate tgt
-peaks of waves
-lines are equal
116
define ultrasound
sound with frequency higher than 20 000Hz
117
define infrasound
sound with frequency lower than 20Hz
118
define normal
perpendicular line from the surface
119
define non- luminous & eg
-reflect light
-moon, pen, book ...
119
define luminous & eg
-produce light
-sun, lamp, torch
120
define monochromatic light
-light of a single λ & 1 colour
121
define critical angle
-when the refracted ray is perpendicular to normal
-varies with medium
122
define total internal reflection
-when incident angle is greater than critical angle, there is not refraction - only reflection
-in transparent medium
- has to be from more n to less n & incident angle is more than C
123
define virtual image
image that cannot be captured on a screen
-laterally inverted
-upright
-virtual
124
define real image
image than can be captured on a screen
125
define image
copy of a real object
126
define focal length
distance btw lens to principle focus
127
define principle focus
where all rays come tgt at a particular point
128
define principle axis
rays that are parallel to each other
