P1 Energy Flashcards
What is the conservation of energy?
Energy can’t be destroyed or created just transfered between different energy stores
Name 8 different energy stores?
Thermal
Kinetic
Gravitational potential
Elastic potential
Chemical
Magnetic
Electrostatic,
Nuclear
How can energy be transfered?
Mechaniclly, by a force doing work.
Electriclly, by work being done by moving charged.
Heating
Radiation
If something happenes what do we know has happened to the energy stores?
They have changed.
Either loosing energy or gaining it to another object in the system or the surrounding energy stores
Eg Thermal stores if friction is involved
What is a closed system?
A system ehere nomenergy can be created or destroyed.
Net Total energy is always = 0
State 2 ways energy can be transfered by:
Heating
doing work
Describe the change of energy when you boil water
Energy is transfered from the kettle’s heating system into the water
Thos causes the waters thermal energy store to increase.
This mean that the water increases in temprature
If work is done then we know what has happened?
Energy has been transfered
What happenes to a balls enery stores as you bring it to a higher altitude?
It’s gravitational potential energy store increases.
As it falls the gravitational potential energy converts into kinetic energy.
If an onject is moving what energy must it have?
Kinetic energy store. When something speeds up it’s kinetic store increases but when it slows down the kinetic energy store will decrease.
How do you calcuate kinetic energy?
Ek=0.5 X M X V^2
Kinetic emergy (Jouls) = 1/2 X Mass (Kg) X Velocity^2 (m/s)^2
What hapens when you lift an object in a gravitational field (earth)
Thos requires work which means that energy is being transfered between stores
The higher an object is the more gravitational potential energy it has.
How do you calcuate Gravitational potential energy (g.p.e)?
g. p.e = MGH
g. p.e = Mass (kg) X Gravitational field strength (N/kg) X Height (meters)
gravitational field strength of earth is 9.8N/kg
What happens when an object falls?
g.p.e is transfered into kinetic energy as it falls and picks up speed.
If there is no air resistance then:
Energy lost from g.p.e = Energy gained in Kinetic energy
But in reall life there is air resistance so some energy will be transfered to other energy stores
MOST OF THE TIME ENERGY WILL BE LOST THROUGH THERMAL MEANS.
What happens to energy stores is something is stretched or squashed?
Energy is transfered into the Elastic potential energy (Ee) stores as long as the limit of proporsion hasn’t been exceded.
