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Physics: ENERGY - Coggle Diagram
Physics: ENERGY
Pretty Important Formulae
Work Done
Work done = force x distance
Units:
Joules = Newtons x metres
Kinetic Energy
Kinetic Energy = mass x speed^2 x 0.5
Units
: Joules = kg x m/s^2 x 0.5
Gravitational Potential
Gravitational Potential = mass x GFS (10) x height
Units
: Joules = kg x 10N/kg x metres
Power
Using Voltage
Power = Current x Voltage
Units
: Watts = Amps x Voltage
Using Work Done
Power = Work Done / Time
Units
: Watts = Joules / Seconds
Electrical Energy
Units
: Joules = Amps x Volts x seconds
Energy = Current x Voltage x Time
Energy = Power x Time
How is it lost?
It's inefficient.
Energy is lost and wasted into other forms
Heat and sound are the most common forms
This is why sometimes when energy is being transferred into others forms,
the amount is less
Transfers by Type of Energy
Mechanically
When an object is moving it gets kinetic energy
Electrically
Current passing through an appliance
By Radiation
Vibrations cause waves to travel through air/vacuums
Transfers by States of Matter
Conduction
Happens only in solids and liquids
Metal are good conductors
Non metals are good insulators
As an object is heated up, the molecules vibrate more and cause nearby molecules to vibrate, transferring energy from hot to cooler parts.
Metals have delocalised electrons; able to move freely among positively charged metal ions. Their molecules vibrate faster than non-metals.
Radiation
No medium required; can travel in vaccum
Black and matt/dull textures are the best emitters and absorbers of radiation
White and shiny texture are the best reflectors of radiation
The higher the temperature and/or the surface area of a body, the more IR radiation is emitted.
Convection
Happens in liquids and gases
When molecules in a fluid has high thermal energy, it moves to replace those with low thermal energy.
Cold liquid is heavy and denser
Examples include water boilers and hot air balloons
Hot liquid is light and less dense (it expands)
The hotter liquid then rises up to less dense AREAS in the fluid. The denser cold liqiud falls down to take its place.