Science: Energy Flashcards
In physics, what is WORK DONE
Work done is the energy transferred when a force is used to move an object a certain distance
What measurement is WORK measured in ?
JOULES
Formula used to calculate WORK DONE (in Joules)?
work done (J) = force (N) × distance moved (m)
What is a force multiplier?
A force multiplier uses a smaller input force (what you apply) to to generate a larger output force (what is created)
Give an example of a FORCE MULTIPLIER
A lever is an example of a force multiplier, a longer lever will require a less input force than a shorter lever to produce the same output force
What happens If you increase the distance of the force applied, from the pivot,
less input force is needed to be used for the same output force as before
What is THERMAL ENERGY + what measurement is it measured in?
The thermal energy of a substance depends on the individual energy of all of the particles, it is measured in Joules (J)
Do faster moving particulars have MORE or LESS thermal energy?
MORE
When particles are heated they begin to move MORE or LESS quickly
MORE
The energy needed to increase the temperature of a substance depends on:
•the mass of the substance
•what the substance is made of
•how much you want to increase the temperature by
What is RADIATION? + give an example
Radiation is a method of transferring energy without the need for particles
An example of radiation is thermal energy being transferred from the Sun to us through space
(where there are no particles)
This type of radiation is known as infrared radiation, it is a type of wave just like light
The hotter an object is the MORE or LESS infrared radiation it will emit (give out)
MORE
The amount of radiation emitted and absorbed depends on:
the surface of the object
Darker matte surfaces absorb and emit more infrared radiation
Shiny and smooth surfaces absorb and emit less infrared radiation, instead reflecting this
What is CONDUCTION
Conduction is the transfer of thermal energy by the vibration of particles
Every time particles collide they transfer thermal energy
Are metals GOOD or BAD thermal CONDUCTORS? + why?
GOOD
As they contain electrons which are free to move
In conduction, thermal energy is transferred from where to where?
From an area with a high thermal energy store (high temperature) to an area where there is a low thermal energy store (low temperature)
Are gases and liquids goofd CONDUCTORS?
NO - as their particles are spread out and so do not collide often, we call these insulators
What is CONVECTION?
Convection is the transfer of thermal energy in a liquid or a gas, it cannot happen without particles
Describe CONVECTION CURRENT
As the particles near the heat source are heated they spread out and become less dense, this means that they will rise
More dense particles will take their place at the bottom nearest the heat source creating a constant flow of particles
This is known as a convection current
Can CONVECTION happen in solids?
Convection cannot happen in a solid as the particles cannot flow, they can only move around a fixed point
