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Science study 2019 Semester 1 (Biology (Pedigrees, DNA, Inheritance and…
Science study 2019 Semester 1
Biology
Pedigrees
DNA
Inheritance and genes
Evoloution
Chemistry
Chemical equations
States of matter in chemical equations
(g) Gas
(l) Liquid
(aq) Aqueous
(s) Solid
Equations must be balanced
Photosynthesis 6CO2 + 6H2O --> C6H12O6+6O2
Balanced equations are when the same number of each element is on each side. Mass cannot be created or destroyed.
Reactant + Reactant = Product
Types of reactions
Decomposition
Combustion
Precipitation
Displacement
Neutralisation
Physics
Describing motion
Distance and displacment
Distance
is the amount travelled. Say you travel 2 km away from your house and back. You have travelled a distance of 4 km.
Displacement
however, is how far your end point is from your start point. In the above scenario, your displacement is 0, as your start and end point were the same.
Another thing to note is displacement doesn't care about obstacles or buildings. If you have to go around buildings, your distance is the length of the path you walked, but displacement it the direct distance between point A and point B
Speed
Speed
is how fast an object moves.
Instantaneous speed
is your speed at a particular moment in time.
Average speed
Is a measure of how fast something moves overall. It ignores stops and changes in speed and assumes the object was travelling at the same speed the whole journey.
Reaction time (Speed and driving)
Reaction time
Is the time it takes someone to react to a sudden change. For a healthy person, this is between 0.15-0.3 seconds.
Reaction distance
is the distance the car goes before the driver reacts to new conditions by swerving or braking. This may be longer than normal if there are distractions in the car.
Breaking distance
The distance a car travels after the breaks have been applied
Stopping distance
The distance before a car stops. Stopping distance = Reaction Distance + Breaking Distance
Formulas
Average Speed = distance/time
Distance = Average Speed x Time
Time = distance/Average speed
Distance/time graphs and speed/time graphs
Time always x axis
Can be displacement graphs, go higher then back down
Horizontal Line on either graph means no movement
Example:
Changes in speed
Acceleration
Acceleration
in physics is not just a change in speed, it measures how quickly the change happens
Average acceleration = an objects change in speed/time taken for that change to occur
