Year 10 Semester 2 Exam Flashcards
What is average speed
Total distance covered divided by total time taken
Easiest way to determine: Distance / Time ratio
- Eg. Average speed of all speedometer readings in a car
What is the Formula for Average Speed
Speed = Distance / Time
Distance = Speed * Time
Time = Distance / Speed
How To Convert From m/s To km/h
1) From m/s to km/s, divide by 1000
2) From km/s to km/hr, multiply by 3600
- Or just multiply by 3.6
How To Convert From km/h To m/s
1) From km/hr to m/hr, multiply by 1000
2) From m/hr to m/s, divide by 3600
- Or just divide by 3.6
What is Instantaneous Speed
Speed of an object at any given instance
When object moves, doesn’t move at steady pace
- Instantaneous speed always changing
- Eg. Speedometer readings in a car
What Are Scalar Quantities
Quantity ignorant of direction
Physical quantity, only has magnitude or size
Eg. Speed, Mass, Temperature, Energy
What Are Vector Quantities
Quantity conscious of direction
Physical quantitiy, has both magnitude and direction
Eg. Displacement, Velocity, Force, Momentum
How Do You Display Vector Quantities
Use head to tail method
Resultant force goes from tail of final force to head of initial force
What is Distance
Amount of total change of location over course of motion
Amount of ground that is covered
What Are The Two Quantities Used to Measure Changing Location
Distance
Displacement
What is Displacement
Overall change in position of object from start to finish
Doesn’t concern itself with accumulation of distance of path
An object can be moving, and have zero displacement
- Eg. Jumping, where person moves up and down, but has no displacement
What is Speed
Quantity that describes how fast or slow an object is moving
What is Velocity
Quantity that is defined as the rate at which an objects position changes
What is Average Velocity
Rate at which an object changes its displacement over time
What is Instantaneous Velocity
Velocity of an object at any given instance
If object moving at unsteady pace, instantaneous velocity always changing
- Eg. A car speeding up
What is Acceleration
Change in velocity with relation to time
What is The Units For Acceleration
m / s^2 or ms^-2
What is The Formula For Acceleration
a = (v - u) / t
v = final velocity ms^-1
u = initial velocity ms^-1
a = acceleration ms^-2
t = time s
What is a Force
Push or a pull that changes an objects motion or it’s shape
What Are Some Common Forces
Friction
Drag
Weight
Normal
Tension
Net Force
What is Friction
Force that resists the sliding or rolling of solid object over another
- More mass = More friction
- More surface area touching = More friction
What is Drag / Air Resistance
Friction between the air and an object
- Friction between the trillions of particles in the air
What is Weight
Force acting on an object due to acceleration or gravity
Measured in Newtons
Object on the moon would have same mass (kg), but different weight (N), than on Earth
What is Normal Force
Force that supports the weight of an object on a surface
What is Tension
Force transmitted through a rope when pulled by forces acting on opposite sides
What is Net Force
Sum of forces acting on an object
What is Newton’s First Law
“Object remains at rest, or if in motion, remains in motion at constant velocity unless acted upon by a net external force”
Example:
- Ball rolling down a hill will continue to roll unless friction or another force stops it
What is Inertia
Object’s resistance to a change in motion
Object remains at rest or in uniform motion in same straight line unless acted upon by external force
What is an Explanation of Normal Force
Stationary object has force of gravity pulling it down
- Doesn’t move because there is another force equal in magnitude in opposite direction
- Since they both act on same object, the object has zero force
What is the Law of Inertia
Inertia keeps an object in existing state of motion
- Larger the mass of object, the more inertia it has, harder it will be to change its motion
- Eg. If you are passenger in car, and not wearing seatbelt, if the car comes to a sudden stop, your body will continue moving forwards, hitting the seat infront of you
What is Newton’s Second Law of Motion
“Acceleration of an object is directly related to the magnitude and direction of the force acting on the object, and inversely related to the mass of the object”
Heavy objects need greater force to move than lighter objects
What Happens if Object Experiences Unbalanced Net Force
If object experiences unbalanced net force, object will change speed, direction or both
If net force in same direction as object, it will speed up (Accelerate)
If net force in opposite direction as object, moving object will slow down (Decelerate) and stop
What is The Formula for Net Force
Net Force = Mass * Acceleration
If mass in kg, acceleration in ms^-2, net force will be in N
Force = Mass * Gravity
What is Freefall
Motion due to gravity on an object
What is Newton’s Third Law of Motion
“Every action has equal and opposite reaction”
What are Action-Reaction Pairs
Where every action has equal and opposite reaction
Action-Reaction act on different objects
- Therefore can’t cancel eachother out
- Eg. If you push someone with 30N force, you get pushed back with 30N force, they don’t cancel out
What are Examples of Action-Reaction Pairs
Walking
- When walking, push backward against the ground with your foot (Action), ground pushes your foot forward (Reaction)
Swimming
- You push water backwards using arms and legs (Action), water exerts equal and opposite force on body, propelling you forwards (Reaction)
Bouncing a Ball
- Exert force by pressing it down onto ground (Action), ground exerts equal and opposite force, causing ball to rebound upwards (Reaction)
What is Energy
Ability to do work
Many forms of Energy: Kinetic, Gravitational Potential, Chemical, Thermal, Nuclear, Electromagnetic, Sonic
What Are The Two Types of Energy
1) Potential Energy
2) Kinetic Energy
What is Potential Energy
Energy associated with an objects height above the ground
What is The Formula For Potential Energy
Potential Energy = mass (kg) * gravity (9.8 ms^-2) * height (m)
What is Kinetic Energy
Energy associated with movement of an object
What is the Formula For Kinetic Energy
Kinetic Energy = 0.5 * mass (kg) * velocity^2 (ms^-1)
What is ‘work’
Measure of the energy transferred to or from an object, is the change in energy
Force applied over a distance
What is the Formula For Work
Work (J) = Force (N) * displacement (m)
Work = Final Energy - Initial Energy
Energy Transfer vs Energy Transformation
Energy transfer is movement of energy from one location to another, stays in same form of energy
Energy transformation is when energy changes from one type to another
What is the Conservation of Energy
“Energy can neither be created nor destroyed, only converted from one type of energy to another”
Total energy of a system is constance
What Happens During Transformation of Energy
Some energy always transformed into form of waste energy during transformations
- Common Types: Thermal, Sonic, Kinetic
What is the Formula For Efficiency
(Total Useful Output / Total Input) * 100 (To convert to percentage)
What is the Lithosphere
Outermost rocky layer of Earth
Made up of upper mantle and crust
- All rocks, minerals, molten magma found on Earth
Approximately 80km thick, very thin in comparison to Earth
Slowest of Earth’s systems to change
Crust of Earth made from magma (Molten rock)
- Is made up of uneven giant plates of rock, covering entire Earth, called Tectonic Plates
- Plates float on semiliquid magma in upper mantle
What is the Atmosphere
Layer of gases commonly called air
Is relatively thin compared to size of Earth
Most important gas for animals is Oxygen, making up 21% of atmosphere
Nitrogen makes up 78% of atmosphere
What are Layers of Atmosphere
More dense at ground level, thins out as you go higher above
Air thins out, until relative emptiness of space
What is Hydrosphere
Made up of all Earth’s water; Oceans & Lakes
- Also water in glaciers, soil and the air
Covers around 70% of Earth’s surface
Hydrosphere interacts with and is influenced by other spheres
- Eg. In atmosphere you can find water in three states: Liquid, Vapour, Solid
What is Cryosphere
Part of hydrosphere that is made up of frozen water
Important in regulating climate on Earth
What is Biosphere
Made up of all living things on Earth
-Includes plants, animals, bacteria
Great interdependence between different parts of living world
Earth is only planet in solar system able to support a biosphere
What is Carbon Cycle
Path through Carbon is exchanged through Earth’s surface
What is Carbon
Carbon is 4th most common element on Earth (After Hydrogen, Helium and Oxygen)
Can cycle through Land, Oceans, Atmosphere
Carbon sinks / Carbon reservoirs are feature of environment that absorbs / stores carbon
What is the Biological / Physical Carbon Cycle
Short-Term cycle, occurs over days, weeks, months, years
Involves cycling of carbon through photosynthesis & respiration
What is the Geological Carbon Cycle
Long-Term cycle, occurs over hundreds to millions of years
Carbon locked in rocks / sediments as fossil fuels (Carbon sinks)
What is Respiration
From Biosphere to Atmosphere
Production of energy using Glucose (Sugar) & Oxygen
All organisms (Including animals, fungi, plants), undertakes respiration to live
What is Decomposition
Biosphere to Atmosphere
Soil (Pedosphere), filled with dead material from plants & other organisms
Decomposers (Eg. Fungi, Bacteria) break down dead material in soil
- Releases carbon dioxide into air, soil, water
What Are the Processes of Carbon Cycle
Respiration
Decomposition
Photosynthesis
Fossilisation
Combustion
What is Photosynthesis
Atmosphere to Biosphere
Plants use energy from sun to make nutrients from Carbon Dioxide
- Makes forests significant carbon sinks
Carbon in form of Carbon Dioxide is converted to sugars during photosynthesis
What is Fossilisation
Rocks (Eg. Limestone), fossil fuels (Eg. Coal, Oil), contain carbon from plants & animals that lived millions of years ago
- When organisms died, slow geologic processes trapped their carbon and transformed it into natural resources
What is Combustion
Reaction of Oxygen and combustible material
- Combustible material holds Carbon
What is the Natural Greenhouse Effect
Natural greenhouse effect critical for maintaining life on Earth
- Solar energy passes through atmosphere and warms Earth’s surface
- Heat gradually leaves Earth’s surface and is radiated back to space
- Some heat is trapped by gases in atmosphere
Why is Natural Greenhouse Effect Important
If heat wasn’t trapped, temperature would drop to -100 degrees at night, rise to 80 degrees in the day
What are the Major Greenhouse Gases
Carbon Dioxide
Water Vapour
Methane
Nitrous Oxides
What are Carbon Sinks and Examples
Feature of environment that absorbs / stores carbon, keeping it from atmosphere
Forests / Plants: Take in large amounts of Carbon Dioxide through photosynthesis
Ocean: Contains dissolved Carbon Dioxide, in shells of marine organisms
Fossil Fuels:Contains carbon from plants & animals that lived millions of years ago, carbon got trapped over time
Limestone: Contains carbon from plants & animals that lived millions of years ago, carbon got trapped over time
How Do Oceans DistributeHeat Around Earth
Ocean currents act like a conveyer belt
- Transports warm water and precipitation from equator towards the poles
- Transports cold water and precipitation from the poles to the tropics
- Regulates global climate, helping to counteract uneven distribution of solar radiation reaching Earth’s surface
What is Thermohaline Circulation For Deep Currents
Deep-Ocean currents driven by differences in water’s density, controlled by temperature (Thermo) and salinity (Haline)
- Therefore thermohaline circulation
What is the Process of Thermohaline Circulation For Deep Currenta
Earth’s polar regions, ocean water gets very cold
- Surrounding seawater gets saltier as when sea ice forms, salt is left behind
- When seawater gets saltier, it gets denser, causing it to sink
- Surface water pulled in to replace sinking water, which becomes cold and salty enough to sink (Eventually)
–Initiates deep-ocean currents driving global conveyer bel
What are Gyres For Surface Currents
Gyre is large system of circular ocean currents formed by global wind patterns and forces created by Earth’s rotation
What are the 5 Major Gyres
North and South Pacific Subtropical Gyres
North and South Atlantic Subtropical Gyres
Indian Ocean Subtropical Gyre.
What is Climate Change Triggered By in Past
Changes triggered by changing configuration of continents and oceans, changes in Sun’s intensity, variations in orbit of Earth, volcanic eruptions
What is the Ice Age
Where thick sheets of ice cover vast amount of areas
Colder global temperature than usual, bigger-than-usual glaciers and ice sheets
What is the Inter-Glacial Period
Times without large ice sheets
Warmer global average temperature
We are currently in warm inter-glacial period, began about 11,000 years ago
What is Permafrost
Permanently frozen ground
- Stores carbon from plant material which was frozen during Ice Age
Temperature of permafrost close to melting
- 2/3’s of Earth permafrost will disappear by 2200
If permafrost does melt
- Will release carbon into atmosphere, equates to half of fossil fuel emissions to date
What is Enhanced Greenhouse Effect
Where extra greenhouse gases in atmosphere trap too much of Sun’s energy, means Earth slowly heats upq
What is Increase in Earth’s Temperature Caused By (Naturally)
Solar Cycles
Sun’s Radiation
Volcanic Activity
Natural Fires
Lightning
By-Products of Animal Metabolism
What is Force Behind Carbon Dioxide Emissions
Industrial Revolution was driving force
- Increased reliance on machines
- Explosive development of manufacturing sector spanning 80 years
Increase in factories caused growth in coal consumption, giving rise to high levels of air pollution
- Greatest impact on environment was emission of Carbon Dioxide from combustion of coal
What are Sources of Methane and Nitrous Oxide Emissions
Landfills
Agricultural Activities
Wastewater Treatment
Industrial Processes
Evidence of Global Warming - Atmospheric Temperature Change
Temperature went up significantly faster after the Industrial revolution, where around 100% of it was from man-made activities
From all the Carbon Dioxide emissions
Evidence of Global Warming - Ocean Temperature Change
Increase in Carbon Dioxide concentration = Warmer waters
- More radiation re-emitted from atmosphere back to surface of Earth
Evidence of Global Warming - Rising Sea Levels
Increase in global warming due to higher concentration of greenhouse gases in atmosphere = More melting of ice caps & glaciers
- Results in increase in sea levels as more water is freed from glaciers, adding volume to sea
- Results in less radiation being reflected from surface, more heat absorbed by Earth’s surface, leads to more melting, making a loop
Evidence of Global Warming - Ice Cover
Increase in global temperature = Melting of glaciers & ice caps
Less radiation reflected from surface, more heat absorbed by Earth’s surface = More ice melting (Positive feedback loop)
What are Fossil Fuel Types
Carbon Dioxide emissions from fossil fuels in 2012, reached 9.2 gigatons of carbon
- Increase of 58% compared to 1990 levels
Coal contributed 43% of emissions
Oil contributed 33% of emissions
Natural Gas contributed 18% of emissions
Abiotic Factors - Temperature Changes
High levels of greenhouse gases in atmosphere increase surface temperature
- As more solar radiation is reflected back
Abiotic Factors - Extreme Weather Events
Changes in Temperature, Rainfall Patterns, Sea Levels
- Lead to floors, fires, droughts
Abiotic Factors - Melting Ice Caps
When ice melts, ability to reflect sun’s radiation reduced
- Leads to increase in global surface temperature
Abiotic Factors - Thermohaline Circulation Disruption
Without movement of rain, air, marine life, new ice age will begin
- Such as North Atlantic Gulf Stream
- What is the role of the Aboriginal fire management regime in reducing GHG emissions
- Use cool burning practices, deliberately lights low-intensity fires during specific seasons, fires burn at slower rate, consuming the undergrowth, and reducing risk of more intense & destructive wildfires
- Cool burning helps to maintain biodiversity, by preventing dominance of certain plant species, promoting healthier ecosystem.
- Fire management aims to protect carbon-rich landscape, like peatlands & dense forests, will help retain stored carbon in soil and vegetation
Describe the effect of Ocean acidification on the Great Barrier Reef
- Corals rely on calcification to build skeletons, ocean acidification reduces availability of carbonate ions in seawater, a key component for coral calcification
- Weakens coral health, making corals more vulnerable to rising sea temperatures and pollution
- Affecting health of corals can lead to decline in biodiversity, as some species struggle to adapt & survive
