Component 5 Flashcards
What energy change occurs when an object is projected upwards?
Kinetic > gravitational potential
What energy change occurs when a moving object hits a obstacle?
Kinetic to sound and thermal
How can energy be stored?
Energy storage is limited
to kinetic, gravitational
potential, thermal, light,
sound and elastic (strain).
What energy change occurs when a vehicle slows down?
Kinetic to thermal
What energy change occurs when an electric kettle boils water?
Electrical to thermal, with sound and kinetic as waste
Can energy be destroyed or created?
No. Energy can be transferred usefully, stored
or dissipated, but cannot be created or
destroyed.
In which ways can unwanted energy transfers be reduced?
Unwanted energy transfers can be reduced
in a number of ways, eg through lubrication
and the use of thermal insulation.
What effects the rate of cooling of a building?
The thickness and thermal
conductivity of its walls.
What does a high thermal conductivity of a material mean?
The higher the thermal conductivity of
a material the higher the rate of energy
transfer by conduction across the material.
So more thermal energy is transferred
What are the two main resources?
- Renewable
- Non-renewable
What are the main renewable sources of energy?
Bio-fuel, wind, hydroelectricity, geothermal,
the tides, the Sun, water waves.
What are the main non-renewable sources of energy?
Fossil fuels (coal, oil and gas), nuclear fuel
How is electricity generated in a power station?
An energy source is used to turn a turbine which turns a generator - meaning electrical energy is produced
What is a force?
A push or pull that acts on an object due to an interaction with another object
What is a contact force?
A push or pull where the objects are physically touching
What is a non-contact force
A push or pull where the objects are physically separated
Name examples of contact forces
Examples of contact
forces include friction, air
resistance, tension and
normal contact force.
Name examples of non-contact forces
Examples of non-contact
forces are gravitational
force, electrostatic force
and magnetic force.
What is “work done”?
When a force causes an object to move
through a distance, work is done on the
object.
What happens when work is done against a frictional force?
Work done against the frictional forces
acting on an object causes a rise in the
temperature of the object.
What is meant by “speed”?
Speed is measured by the distance
travelled in a certain time
How do you calculate speed?
Simple calculations of average speed
using the equation: speed = distance/time
will be required.
Give some examples of units of speed
Units of speed include metres per second,
kilometres per hour and miles per hour.
If a car moves 80 miles in 2 hours, what speed it is moving at? Please include a unit.
REMEMBER: Speed=distance/time
80/2=40 miles per hour
How do you calculate stopping distance?
Stopping distance = braking distance + thinking distance
What is thinking distance?
the distance the vehicle travels
during the driver’s reaction time
What is braking distance?
The distance it travels under
the braking force
What happens to stopping distance when the speed of a vehicle is larger?
For a given braking force the greater
the speed of the vehicle, the greater the
stopping distance.
What effects human reaction time?
- Tiredness
- Distraction
- Drugs
- Alcohol
- Practice
What effects braking distance?
The braking distance of a vehicle can be
affected by adverse road and weather
conditions (Icy, wet), and poor condition of the vehicle (worn brakes/tyre treads).
What is radioactive decay?
- Random process
- Unstable atomic nuclei
- The nucleus gives out ionising radiation
What are the 3 radioactive particles?
- Alpha
- Beta
- Gamma
What can stop alpha radiation?
Hand
What can stop beta radiation?
Aluminium (~3mm)
What can stop gamma radiation?
Lead
Which radiation is easiest to stop?
Alpha
What are the uses of radiation?
Sterilising medical equipment (Gamma)
Standardising thickness of aluminium foil (Beta)
Radiotherapy for cancer
