Energy Flashcards
A meteorite enters the Earth’s atmosphere and burns up before reaching the Earth itself. The meteorites’ kinetic energy store is transferred to the __________ store of the surroundings.
thermal
Kinetic energy = ___ × mass × speed²
1/2
Kinetic energy = 1/2 × mass × ______
speed²
_______ _______ = 1/2 × mass × speed²
kinetic energy
True or false? A system must contain more than one object.
false
A _______ is an object or a group of objects.
system
A system is an _______ or a group of _______s.
object
A system is an object or a _______ of objects.
group
When an object is in a gravitational field, it has energy in its __________ __________ energy store.
gravitational potential
When an object is raised to a height, it has __________ __________ energy stored.
gravitational potential
Most meteorites that enter the Earth’s atmosphere burn up before they reach the Earth itself. When this happens, which of the meteorites’ energy stores decreases?
kinetic energy
What units are used for gravitational potential energy?
joules
In the equation for elastic potential energy below, what is represented by the symbol k?
Ee = ½ke²
spring constant
Elastic potential energy = ½ × ______ ________ × (extension)²
spring constant
Elastic potential energy = ½ × spring constant × ____________
(extension)²
Elastic potential energy = _ × spring constant × (extension)²
½
______ _________ _______ = ½ × spring constant × (extension)²
Elastic potential energy
What is the unit of measurement for energy?
joules
As the speed of an object increases, the __________ energy of the object increases.
kinetic
_____________ __________ _______ = mass × gravitational field strength × change in height
Gravitational potential energy
Gravitational potential energy = _____ × gravitational field strength × change in height
mass
Gravitational potential energy = mass × _____________ _______ _________ × change in height
gravitational field strength
Gravitational potential energy = mass × gravitational field strength × ______ __ _______
change in height
The kinetic energy of an object depends upon its speed and its… what?
mass
When a car is driving, some of the __________ energy stored by the fuel is transferred to the kinetic energy of the car.
chemical
A battery stores __________ energy.
chemical
A battery powered lamp transfers energy to the thermal store of the surroundings by heating. What energy store of the battery decreases as the thermal store of the surroundings increases?
chemical energy
A catapult uses a material that can be stretched to propel an object. When the object is released, the catapults’ _________ _________ energy store decreases and energy is transferred to the kinetic energy store of the object.
elastic potential
Apart from height above ground, what other quantity affects how much gravitational potential energy an object on Earth has stored?
mass
How does increasing the speed of a motorbike change the amount of energy in its kinetic energy store?
increases it
True or false? If the speed of an object doubles, its kinetic energy will also double.
false
What unit is used to measure energy when calculating specific heat capacity?
joules
Specific heat capacity of a material is the energy needed to raise ___ of a material by 1°C.
1kg
Specific heat capacity of a material is the energy needed to raise 1 kg of a material by _°C.
1
change in thermal energy = mass of water × specific heat capacity of water × ______________ ________
temperature change
change in thermal energy = mass of water × ________ _____ __________ __ ______ × temperature change
specific heat capacity of water
change in thermal energy = _____ __ _____ × specific heat capacity of water × temperature change
mass of water
_______ __ ________ _________ = mass of water × specific heat capacity of water × temperature change
change in thermal energy
The smaller the temperature difference between an object and its surroundings, the ______ the temperature will change.
slower
The ________ the temperature difference between an object and its surroundings, the slower the temperature will change.
smaller
When an object is raised vertically, work is done against __________.
gravity
_____ _____ = force × distance
work done
Work done = _____ × distance
force
Work done = force × _________
distance
The amount of energy transferred per unit time by an electrical appliance is measured in what?
watts or kilowatts
What name is given to the amount of work done in a given time?
power
What is the name for the amount of energy transferred every second by an electrical appliance?
power
______ = energy transferred / time
power
power = _______ ___________ / time
energy transferred
power = energy transferred / ____
time
The total amount of energy transferred by an appliance depends on power and __________
time
Samuel pushes against a door with a force of 10N, but the door doesn’t move. Has Samuel done work on the door?
no (object hasn’t moved)
When stated as a percentage, the useful energy transferred by a device divided by the total energy supplied to the device is known as the device’s __________
efficiency
True or false? When two objects are touching, the material the surface is made from does not effect the rate at which the object transfers energy by heating.
false
__________ = (useful energy output / total energy input) × 100
efficiency
Efficiency = (________ _________ _______ / total energy input) × 100
useful energy output
Efficiency = (useful energy output / ____ _______ _____) × 100
total energy input
Efficiency = (useful energy output / total energy input) × ___
100
Thermal insulation and lubrication are two ways to reduce unwanted __________ transfers.
energy or heat
When electric currents are used to transfer energy, the energy is transferred ___________
electrically
When ________ ________ are used to transfer energy, the energy is transferred electrically
electric current
Energy can never be created or destroyed. True or false?
true
It is hot outside, and the air conditioning has been turned on inside two buildings. Building A’s walls contain insulation, but Building B’s do not. Which building is more likely to cool faster?
building A
What name is given to a material that does NOT conduct thermal energy well?
insulator
A material that does not conduct electricity is called an __________
insulator
Material A has a higher thermal conductivity than Material B. Which material will transfer energy by conduction faster?
material A
Nuclear power stations use the nuclear energy stored in nuclear fuel to increase the temperature of water. Which of the water’s energy stores increases?
thermal
Energy can never be stored. True or false?
false
Filament bulbs dissipate energy to the __________ energy store the surroundings because they get very hot.
thermal
A particular solid is an excellent conductor of thermal energy. Is it more likely to be a metal or a non-metal?
metal
Certain specialised devices can be more than 100% efficient. True or false?
false
Suggest a form of renewable energy that could be used to power an electric ticket machine that only needs to work during daylight hours.
solar
What name is given to the method of electricity generation that uses hot rocks inside the Earth to produce steam and drive a turbine?
geothermal
True or false? One of the advantages of nuclear power is that once the nuclear fuel has been used, its waste is no longer radioactive.
false
True or false? The ultimate source of the electricity produced by a wind turbine is the Sun.
true
Are the running costs of wind turbines generally high or low?
low
True or false? Fossil fuels are a renewable energy resource because they are formed from living things.
false
True or false? One disadvantage of wave power is that it pollutes the sea.
false
Name a fossil fuel that formed from plant material over millions of years.
coal
True or false? Wind is a renewable energy source.
true
Fossil fuels are formed gradually over __________ of years.
millions
Tidal barrages are a reliable way to produce electricity at predictable times. True or false?
false
Hydroelectric and wave power both use the movement of water to drive a turbine and produce electricity. Name one other way of generating electricity that uses the movement of water.
tidal
Tidal barrages are beneficial to local wildlife. True or false?
false
Do wind turbines produce a constant supply of electricity?
no
People living near wind farms sometimes object to them because of visual pollution and what other form of pollution?
noise
What name is given to a fuel made from living organisms (such as wood) or their waste?
biofuel
Do wind turbines contribute to climate change as they generate electricity?
no
What standard units are used for power?
watts
The total amount of energy transferred by an appliance depends on power and __________.
time
What is a closed system?
system where no energy can be transferred to or from the surroundings - the total energy in the system is the same
What is a system?
an object or group of objects
