Chapter 9 Flashcards
im bored yall π© (69 cards)
1
Q
How do forces in nature affect us?
A
Tsunami
- surface of Earth consists- large pieces of rocks plates
- plates- float on a semi- liquid layer- asthenosphere
- move slowly/continuously
Global warming
- result- increase in surface tempt of seas/oceans
- longer/intense storms
2
Q
What is a force?
A
Push or pull
3
Q
What is force measured by and SI unit of force?
A
- Spring balance/Newton meter
- SI unit: Newton (N)
4
Q
What are the two types of forces?
A
- Contact forces
- Non contact force
5
Q
What is contact force?
A
- force that acts when object touch
- exp: friction
6
Q
What are non-contact forces?
A
- forces that act at a distance from an object
- exp: magnetic force, electric force, gravitational force
7
Q
What is friction?
A
- force that opposes motion between two surfaces in contact
8
Q
How to reduce friction?
A
- streamed shapes- reduce water/air resistance
9
Q
What is elastic force/tension?
A
- force acting on stretched/compressed elastic object to return to its original state/shape
- when elastic object is stretched/compressed- resists change in shape- exert force in opposite direction
10
Q
What is Gravitational force?
A
- force pulls all objects towards earth
- gravity works on any two objects with mass
- weight of object= gravitational force acting on object
- increase mass, increase weight
11
Q
What is the SI unit of gravitational force?
A
Newtons (N)
12
Q
What is electrical force?
A
- 2 charged objects- experience electrical force of repulsion/attraction without direct contact
- Like charges- repel
- Unlike charges- attract
13
Q
What is magnetic force?
A
- 2 magnets- experience magnetic force of repulsion/attraction without direct contact
- Like poles- repel
- Unlike poles- attract
- Magnets (only attract with magnetic materials)- attract objects made from iron/steel/nickel/combalt
14
Q
How do maglev trains work?
A
- Magnets in track and train- repel and lift slightly above track
- No contact- friction, greatly reduced- allow train to move very fast
- Maglev train- experience mainly air resistance
15
Q
What is mass?
A
- measure of amount of matter in an object
16
Q
What is mass measured with and SI unit?
A
- Beam balance/electronic balance
- SI unit: kilograms (kg)
17
Q
What is amount of matter equal to?
A
Amount of matter= number of atoms/molecules making up the object
18
Q
Is it possible to have mass but no weight?
A
YES!
19
Q
How is weight/gravitational force created?
A
When 2 or more masses interact, exert mutually attractive force on each other
20
Q
What is the relationship between mass and weight? (formula)
A
weight= mass x constant value of gravity
In simple terms, w= m x g
21
Q
what is the constant gravitational force on earth?
A
10N/Kg
22
Q
What is the difference between mass and weight?
A
Weight
-Gravitational force exerted on an object
- May change based on location
- SI UNIT: Newton (N)
- Spring balance
Mass
- amount of matter in an object
- CONSTANT no matter location
- SI UNIT: Kilogram (Kg)
- Electronic balance, beam balance
23
Q
How is motion charactized by?
A
- how fast an object is
- direction of its movement
24
Q
What does it mean when a object is in motion?
A
It means the object is moving
25
What are some examples of changes in motion?
- initially starts to move
- moving at constant speed=slow down
- moving at constant speed=speed up
- change direction of movement
- stops moving
26
When there is no changes to motion what are the two ONLY possible outcomes?
- remains stationary (initally at rest)
- move- constant speed in straight line
27
Is it possible for an object to be in motion when the net/resultant force acting on the object is zero?
Yes it is possible
27
What can a force do? (6 points :)
**-move a stationary object
- change speed of object
- stop a moving object
- change direction in which object moves**
- cause a turning effect to about object about a pivot
- change shape/size
| BOLD- changes in motion of an object
27
What else changes when there is changes in motion?
changes way of movement
28
What happens if the net/resultant force is zero at all times?
object can only move with constant speed in a straight line/remain at rest if initally resting
28
What happens when there is no net force?
- Motion- remains unchanged
- If object is moving, can only move with constant speed in a straight line
29
What can a net/resultant force do?
- cause a change in state motion of object
30
What does motion consists of?
- speed
- direction of travel
31
What does it mean when there is changes to motion? (in terms of net force)
net force IS acting on object
ur mom π
31
What is pressure? πΎππππππ πΏπππππ
-effect of force acting on an object
-amount of force acting per unit area
32
What does pressure depend on?
-force
-area
32
Why is there greater pressure?
Force acts on smaller area, higher pressure
32
What is an example of pressure?
If bag hung on one shoulder- more pressure
If bag hung 2 shoulders- pressure- lesser exerted on each shoulder
33
What is the formula and SI unit of pressure?
Formula:
Pressure= force/contact area
SI unit:
Pascal/Newton per square meter
34
1 example of pressure in daily life
- injection- very sharp- area of contact with needle with skin- very small- high pressure
35
What is the relationship between pressure and depth of water?
Higher water pressure with an increasing depth
36
What are 2 examples of pressure in liquid in daily life?
Dam
- base of dam- thicker than its top
- why?- water pressure higher at bottom
- thicker wall- able to withstand high pressure
Submarine
- pressure deep below water surface- high
- thus, submarine needs strong body to withstand high pressure
36
Characteristics of air particles
- light
- still occupy space
- have mass
37
What is atmospheric pressure?
- force exerted by layer of air per unit area
38
Examples of Atmospheric pressure
Drinking straw
- suck on straw, some air removed
- air pressure decreases, decreases atmospheric pressure
- higher atmospheric pressure- pushes liquid up straw into mouth
Suction cup
- press suction cup hook against smooth surface, air is pushed from under suction cup
- air pressure between cup and surface decreases, decreases atmospheric pressure
- lower atmospheric pressure helps to hold it in place
39
MEGAN SUCKS
YES :) hehe π©
40
How is energy and force related?
in terms of work done
41
What is the definition of work done?
process of energy transfer
42
Define work
use of a force to move an object in the direction of the force
43
What are the conditions needed for work to be done?
- there is a force acting on the object
- object moves through a distance
- object moves in direction of the force
| IF ANY ABSENT, NO WORK IS DONE
44
What is the formula for work done?
- work done: force x distance moved in direction of force
simple terms: W.D= FxD
45
What is the SI unit for energy
Joules (J)
46
What is the law of conservation of energy?
- energy cannot be destroyed or created
- energy can be converted from one form to another/transferred
47
Common sources of energy
Fossil fules
47
What is fossil fuels, explain
-formed from remains of dead plants/animals (millions years ago)
-fossil fuels burnt, undergo chemical process, release heat energy converted to KE used to produce electrical energy
-conversion: chemical potential energy---heat energy---kinetic energy---electrical energy
48
Impact of the use of fossil fuels on the environment
-releases air pollutants and greenhouse gases (carbon dioxide_
- contribute to global warming, increases rate of climate change- natural disasters
49
OTHER ALTERNATIVE sources of energy (points only)
-solar energy
- hydroelectric energy
- wind energy
- geothermal energy
- biofuels
-nuclear energy
50
Explain how solar energy works and the conversion of energy
-made of materials that captures sunlight to convert light energy to electrical energy
- conversion: light energy--electrical energy
51
Impact of the use of solar energy on the environment **SPECIAL** (advantage)
-although it generates electricity without releasing air pollutant, sufficient care needs to be taken to reduce amount of toxic waste during production and disposal of solar panels
52
Explain how hydroelectric energy works and conversion of energy
- electrical energy generated by turbines when moving powers them
- hydroelectric power station stores water in reservoir behind dam
- when water released from dam, moving water powers turbines to generate electricity
- conversion: GPE---K.E (water)---K.E(turbine)--Electrical energy
53
Impact of the use of hydroelectric energy on the environment
- reservoirs flood and area near there, flooded
- affects plants/force animals to move to other area
54
Explain how wind energy works and conversion of energy
-energy from wind to electrical energy
-wind blows at the wind turbine, KE of wind is transferred to blades of the turbine, blades rotate
-generator connected to the turbine spins, generates electrical energy
- conversion: K.E (wind)---K.E (wind turbine)---electrical energy
55
Impact of the use of wind energy on the environment
- large plots needs to be cleared to build
- loss of wildlife- natural habitats--destroyed
- Nosie pollution when blades turn
56
Explain how geothermal energy works and conversion of energy
- heat stored in Earth
- geothermal power plant- uses heat from deep inside Earth to generate steam, powers a turbine to produce electricity
- conversion: Heat energy (earth's core)---K.E (steam)---K.E(turbine)---electrical energy
57
Impact of the use of geothermal energy on the environment
- large areas/lots of land need=habitats loss
58
Explain how biofuels works
- made from animal waste/plant materials
- produced from recycling of food waste
- used to power motor vehicles
- carbon dioxide produced by vehicles- reabsorbed by plants when they make food
59
Impact of the use of biofuels on the environment **SPECIAL** (advantage)
- releases air pollutant
- ADVANTAGE: plants used to make biofuels can be grown in short time/recycle/reduce waste :)
: balances carbon dioxide intake and release
60
Explain how Nuclear energy works and conversion of energy
- nucleus of an atom
- can be obtained through nuclear reactions and converted to electrical energy
-nuclear power plants generate electrical energy using heavy atoms
- when heavy atom splits into smaller atoms a large amount of heat is released which is used to boil water then forms steam- power turbine-electricity
- conversion: nuclear energy---heat energy---K.E---electrical energy
61
Impact of the use of nuclear energy on the environment **SPECIAL** (advantage)
-newer and safer way to generate energy from nuclear reactions (lesser land/clean energy)
-minimize risk of health/safety of communities living near nuclear power plants
