P1 motion, forces and energy Flashcards
1
Q
meaning of prefix “centi”
A
/100
2
Q
meaning of prefix “milli”
A
/1000
3
Q
meaning of prefix “kilo”
A
*1000
4
Q
meaning of prefix “mega”
A
*1 000 000
5
Q
meaning of prefix “giga”
A
*1 000 000 000
6
Q
how to read this
A
4.33 seconds
NOT 4 seconds 33 milliseconds (milliseconds are thousandths of a second, not hundredths)
7
Q
what is a scalar quantity
A
measurement that has magnitude only
8
Q
what is a vector quantity
A
measurement that has magnitude and direction
9
Q
scalar or vector? distance
A
scalar
10
Q
scalar or vector? speed
A
scalar
11
Q
scalar or vector? time
A
scalar
12
Q
scalar or vector? mass
A
scalar
13
Q
scalar or vector? energy
A
scalar
14
Q
scalar or vector? temperature
A
scalar
15
Q
scalar or vector? force
A
vector
16
Q
scalar or vector? weight
A
vector
17
Q
scalar or vector? velocity
A
vector
18
Q
scalar or vector? acceleration
A
vector
19
Q
scalar or vector? gravitational field strength
A
vector
20
Q
define speed
A
distance travelled per unit time
21
Q
equation for speed
A
v = d/t
22
Q
equation for average speed
A
23
Q
define velocity
A
speed in a given direction
24
Q
define acceleration
A
change in velocity per unit time
25
equation for acceleration
26
how to find the speed on a distance-time graph
gradient
27
how to find the distance travelled from a speed-time graph
area under the line
28
how to find acceleration from a speed-time graph
gradient
29
object moving with increasing speed called?
acceleration
30
object moving at decreasing speed called?
deceleration
31
what is the acceleration of free fall
32
define mass
a measure of the quantity of matter in an object
33
define weight
- the gravitational force on an object that has mass
- the effect of a gravitational field on a mass
34
define gravitational field strength
the gravitational force per unit mass
35
equation for gravitational field strength
36
what is gravitational field strength near the surface of the earth
9.8 N/kg
37
relationship between gravitational field strength and acceleration of free fall
equivalent
38
define density
mass per unit volume
39
equation for density
40
how to find density of regularly shaped solid
1. find mass of object using balance
2. measure dimensions of object and calculate volume
41
how to find density of liquid
1. place empty measuring cylinder on balance and tare so it reads 0
2. pour liquid into measuring cylinder. record mass from balance and volume from measuring cylinder
42
how to find density of irregularly shaped solid
1. measure initial volume of liquid by taking reading from measuring cylinder
2. place solid in water. take new reading, repeat with diff starting amts of water to get accurate volume of solid (if solid doesnt fit, use EUREKA CAN. water displaced into measuring cylinder, giving v of solid)
4. calculate v of pebble, take mean and calculate density
43
density of water
44
1dm^3 = ?L
1
45
how to know if object will float on surface of liquid
average density is lower than that of liquid = float
46
how may forces change an object
- size
- shape
- motion
47
how to determine resultant force?
add forces
48
define friction
- force between 2 surfaces
- may impede relative motion and produce heating
49
friction in water is known as?
drag
50
friction in gas is known as?
air resistance
51
newton first law?
- an object either remains at rest or continues in a straight line at constant speed
- unless there is a resultant force on the object
52
newton 2nd law
F = ma
53
direction of resultant force vs acceleration?
same direction
54
which axis does the iv go on
x-axis
55
which axis does the dv go on
y-axis
56
define the spring constant
force per unit extension
57
equation for spring constant
58
define "limit of proportionality"
- highest force that can be applied
- before extension of a spring or wire no longer proportional to force applied
- deformation occurs after this point
59
describe the moment of a force
measure of its turning effect
60
define the moment of a force (equation)
moment = force * perpendicular distance from pivot
61
when is an object in equilibrium
no resultant force, no resultant moment
62
define centre of gravity
- imaginary point within object
- that mass and weight of object evenly dispersed around
63
where is centre of gravity in regular shapes
at a point along the lines of symmetry
64
how does position of centre of gravity affect stability of object
- vertically above base = stable
- low centre of gravity and wide base = more stable
65
how to find centre of gravity of irregularly shaped plane lamina
- suspend object from multiple points
- hang plumbline and draw vertical lines along it
- find point at which all vertical lines intersect
66
in what states can energy be stored
- kinetic
- gravitational potential
- chemical
- elastic (strain)
- nuclear
- electrostatic
- internal (thermal)
67
types of energy transfer
- mechanical work
- electrical work
- waves
- heat
- electromagnetic
68
event or process involving mechanical work
forces
69
event or process involving electrical work
electric currents
70
event or processes involving waves
light and sound
71
equation for kinetic energy
72
equation for change in gravitational potential energy
73
principle of conservation of energy
- energy cannot be created or destroyed,
- only transferred from one store to another
74
equation for mechanical working
75
how is useful energy obtained from fossil fuels
- heat from fuel boils water to produce steam
- high pressure steam turn turbines
- makes generator spin at high speed, which generates electricity
76
how is useful energy obtained from waves
- movement of waves up and down drives turbines
- spin generator at high speed, generating electricity
77
how is useful energy obtained from tides
- trap seawater behind dam (barrage) wall
- water at high tide trapped behind barrage to produce flow of water through turbines, making them turn
- spins generator at high speed, generating electricity
78
how is useful energy obtained from hydroelectric dams
- build dam wall on river
- hold water behind wall, large height difference between upstream and downstream
- rush downstream through turbine blades, spin generator
79
how is useful energy obtained from geothermal resources
- cold water fed through pipes underground, return as steam due to volcanic activity
- steam drives turbines, spin generators to generate electricity
80
how is useful energy obtained from nuclear fission
- use nuclear reaction to produce heat
- boil water to produce steam
- spin turbines, spin generators to generate electricity
81
how is useful energy obtained from solar cells
- produce electricity directly from electromagnetic waves in sunlight
82
how is useful energy obtained from solar thermal collectors
- absorb IR waves from sun
- heat water
83
how is useful energy obtained from wind turbines
- wind spins turbine
- spin generator
84
advantages of fossil fuels as an energy resource
- high power output
- 24/7 output
- cheap to build
85
disadvantages of fossil fuels as an energy resource
- non-renewable
- produce greenhouse gases
86
advantages of waves as an energy resource
- renewable
- no greenhouse gases
87
disadvantages of waves as an energy resource
- new technology, not reliable
- low power output
88
advantages of tides as an energy resource
- renewable
- no greenhouse gases
- high power output
89
disadvantages of tides as an energy resource
- need high tides, not common
- blocks large area of sea
- expensive to build
90
advantages of hydroelectric dams as an energy resource
- renewable
- no greenhouse gases
- high power output
91
disadvantages of hydroelectric dams as an energy resource
- disrupt animal habitat, displaces people
- need big river
- expensive to build
92
advantages of geothermal resources as an energy resource
- renewable
- no greenhouse gases
- reliable output
93
disadvantages of geothermal resources as an energy resource
- only few volcanic countries
- relatively low power output
94
advantages of nuclear fission as an energy resource
- high power output
- 24/7 output
- no greenhouse gases
95
disadvantages of nuclear fission as an energy resource
- non-renewable
- radioactivity risks
- very expensive to build
96
advantages of energy from the sun as an energy resource
- renewable
- no greenhouse gases
97
disadvantages of energy from the sun as an energy resource
- unreliable, need sunshine
- low power output
- expensive to build
98
how is energy released in the sun
nuclear fusion
99
how is energy released in nuclear reactors
nuclear fission
100
equations for efficiency
101
define power
- work done per unit time
- energy transferred per unit time
102
equations for power
103
define pressure
force per unit area
104
equation for pressure
105
how does pressure vary with force
directly proportional to force
106
how does pressure vary with area
inversely proportional to area
107
1Pa = ?N/m^2
1
108
1N/cm^2 = ?Pa
10 000
