Energy Flashcards
What does it mean by “Energy is dissipated”?
Energy which is dissipated is spread out or wasted
What is energy?
Energy is the ability to do work
When work is done BY an object, energy is ____________________
When work is done BY an object, energy is TRANSFERRED FROM THE OBJECT.
How many joules in a mega joule?
1000000J = 1MJ
What is the “Principle conservation of energy”
The total amount of energy in a closed system is constant
What is a closed system?
A closed system is where no energy can be added or none can escape
What is kinetic energy?
The energy possessed by a moving object
What is chemical energy?
The energy in between atoms etc batteries.
What is thermal energy?
The energy of the random motion of particles in an object.
What is gravitational potential energy?
The energy an object has due to its position in a gravitational field.
What is electrostatic energy?
The energy an object has due to its position in an electric field.
What is elastic potential energy?
The energy stored in an object when its shape is changed.
What is limit of proportionality?
When a spring cant revert back to its original shape.
How can we reduce the amount of energy dissipated from a system?
Lubrication: Reduces friction between moving parts of the machine.
Making vehicles streamlined: reduces air resistance exerted on them.
Using low resistance cables in an electric circuit: Reduces amount of energy dissipated as heat.
Thermal insulation: Reduces the rate of thermal energy being transferred to the building.
What is the law of conservation of energy?
Energy can be transferred usefully, stored or dissipated but it cannot be created or destroyed.
When is work done?
Work is done whenever energy is transferred from one store to another.
What is mechanical work?
Mechanical work involves using a force to move an object
What is electrical work?
Electrical work involves a current transferring energy
What is power?
Power is the rate at which energy is transferred.
Or
Power is the rate at which work is done
What are the measurements for Power = Energy Transferred / Time
Power = Watts (W)
Energy Transferred = Joules (J)
Time = Seconds (s)
What are the measurements for Elastic potential energy = 0.5 x spring constant x Extension
Elastic potential energy = Joules (J)
Spring Constant = N/m
Extension = metres (m)
Name 3 ways to reduce heat being dissipated from home ( Thermal Insulators)
Cavity wall insulation
Triple / Double glazing glass windows
Loft insulation
What is efficiency?
The ratio of useful output energy transfer to the total input energy transfer
Or
The ratio of useful power output to the total power input
What is a non renewable resource
A resource that is finite and will eventually run out.
