Science MCQ Test T4 Flashcards
What are the energy transformations and transfers involved in Indigenous Traditional fire making?
Kinetic energy is transformed into (predominantly) thermal energy, light energy, and sound energy
Kinetic energy is TRANSFERED from your moving hands to the stick as you rub it between your hands
What are the two methods of fire starting in Aboriginal culture?
- Hand drill
- Fire saw
What is the difference between energy TRANSFORMATIONS and energy TRANSFERS
Energy transformations is when the type of energy is changed, and energy transfers is when the energy is passed on from one object to another.
What are 3 examples of energy transformations
- Flash light:
Chemical (battery) –> Light energy - Car:
Chemical (battery) –> mechanical, light, sound, thermal - Phone
Chemical energy + Electricity (charger) –> Light, sound, heat, chemical
What are the 9 types of energy?
(Head, NECK, LEGS)
- Heat (thermal) energy
- Nuclear energy
- Electrical energy
- Chemical
- Kinetic (remember this includes mechanical!)
- Light
- Elastic (potential)
- Gravitational (potential)
- Sound
What types of energy are considered ‘kinetic’?
kinetic energy includes radiant energy, sound energy, heat energy and electrical energy
What is energy measured in?
Joules (J)
Kilojoules (kJ)
Megajoules (MJ)
How many joules are in a kilojoule?
1000 joules
convert 10 kilojoules to joules
10 x 1000
= 10 000
convert 115.5 mJ to kilojoules
115.5 x 1000
= 115500kJ
convert 2300J to MJ
2300 / 1000 000
= 0.0023MJ
Recall the Law of the Conservation of Energy
Energy cannot be created nor destroyed, (but it can change forms)
What is the formula for calculating energy efficiency (percentage)
Efficiency =
useful output energy
—————————– x100
total input energy
What does the downward pointing arrow mean in a sankey diagram
The down arrow represents the wasted energy
What are the 9 advantages of owning an electric vehicle?
- Eco-friendly: Zero exhaust emissions.
- Energy Efficient: More efficient than petrol engines.
- Cost Savings: Cheaper to run and maintain.
- Renewable Energy: Can charge with solar or wind power.
- Quiet: Reduces noise pollution.
- High-Tech: Includes the latest technology and safety features.
- Incentives: Tax breaks and rebates.
- Health Benefits: Reduces air pollution.
- Performance: Instant acceleration and torque.
What are the disadvantages of owning an EV
- Range: Limited driving distance per charge.
- Charging Time: Takes longer to recharge compared to refueling.
- Charging Infrastructure: Fewer charging stations compared to petrol stations.
- Upfront Cost: Generally higher purchase price.
- Battery Life: Batteries degrade over time and can be costly to replace.
- Range Anxiety: Fear of running out of charge on longer trips.
- Electricity Source: If the electricity is from non-renewable sources, it reduces environmental benefits.
- Heavy Weight: Batteries add significant weight, affecting handling and performance.
- Limited Model Availability: Fewer models and choices compared to traditional cars.
- Recycling: Challenges with recycling batteries and electronic components.
What are the 9 physical features of an electric car
Electric Motor
Battery Pack
Charging Port
Regenerative Braking System
Aerodynamic Design
LED Lighting
Digital Dashboard
Touchscreen Interface
Compact Engine Bay
Define potential energy
Potential energy is the energy STORED within an object due to its position, arrangement or state.
Define kinetic energy
Energy that is moving
- has many forms
What are the 3 types of potential energy
- Gravitational
- Chemical
- Elastic
What unit is used to measure MASS
kg
What unit is used to measure WEIGHT
N (newtons)
What is the common units for acceleration due to gravity (in general)
m/s squared
What is the rate for acceleration due to gravity ON EARTH
9.8m/s squared
*note that m/s2 is only the units for the acceleration for gravity! Don’t include it in my calculation!!!!!!!!!!
What is the rate for acceleration due to gravity ON THE MOON
1.625m/s squared
*note that m/s2 is only the units for the acceleration for gravity! Don’t include it in my calculation!!!!!!!!!!
What is the formula for calculating the weight of something
W = m x g
weight = mass x acceleration due to gravity
What is the difference between mass and weight?
Weight: When you step on a scale it shows your weight as a number. This number is actually a measurement of the gravitational pull Earth has on you.
Mass: Is how much “stuff” you are made of. Unlike weight, your mass is the same whether you are on Earth, on Mars, on the moon, or any other planet
Define energy
Energy is the ability to do work
What is the formula to calculate the GPE of an object
PE = mgh
m = mass
g= 9.8 m/s squared
h = height in metres
What is weight of an 85kg person on the earth?
833N
What is the mass of an object that weighs 85N on earth?
85 / 9.8
= 8.673469
= 8.67kg (2dp)
TRUE/FALSE: An objects’ mass and height above the ground directly influences it’s gravitational potential energy
TRUE
What is the units for gravitational potential energy
JOULES
(J)
*because it is energy
What do I use to remember how to calculate GPE
PE = mike gets hot
(PE = m x g x h)
is joules for the unit a capital j or lowercase
CAPITAL J
(J)
What is the formula for calculating KE
KE = 1/2 mV squared
m = mass of an object
V = velocity of an object
1/2 = half
For the KE formula, is both the m and v halved, or just the mass (m)
The whole thing is halved
Define velocity
The velocity of an object refers to the rate at which the object changes its position.
It is denoted by v.
Unit of velocity is m/s.
Define mass
Mass of an object or body refers to how much matter is in the object.
It is denoted by m.
Unit of mass is kg.
Does an object’s mass and velocity directly impact its kinetic energy?
YES
How many kilojoules are in a megajoule?
1000
How many joules are in a megajoule?
1 000 000
What is the notation for megajoules
MJ
what is the notation for kilojoules
kJ
what is Kinetic Energy measured in
JOULES (J)
- because just like GPE, it is measuring energy, and so therefore is measured in joules
how do I calculate velocity
v = d / t
velocity = distance (metres) divided by time (seconds)
Give an example of how stretching/compressing etc an object increases its potential energy
e.g stretching a rubber band increases its elastic potential energy
What are the key difference between EVs and petrol vehicles?
- EVs have less tailpipe carbon emissions
- EVs convert chemical energy in batteries to ELECTRICAL energy, and then kinetic energy
- But petrol cars transform chemical energy in fuel to heat and mechanical energy etc that moves the car
- EVs are more energy efficient than petrol cars
What type of energy is produced by the sun
Nuclear
Describe the energy transformation/s present in an arrow being drawn in a bow and then released
Elastic potential energy –> kinetic energy (with a bit of heat and sound)
Distinguish between gravitational, chemical and elastic potential energy
Gravitational: an objects potential energy due to it’s position
Chemical: an object’s potential energy due to its composition
Elastic: an object’s potential energy due to its state/shape
