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P1- Conservation and Dissipation of Energy (Yr9) - Coggle Diagram
P1- Conservation and Dissipation of Energy (Yr9)
Energy stores
Kinetic- in a moving object.
Chemical- a food, battery or fuel.
Gravitational Potential- an object above the ground.
Elastic potential energy- a stretched or strained object.
Thermal- due to a substances temperature.
Magnetic- 2 separated magnets (attract or repel)
Nuclear- Radioactive decay.
Energy transfers
Waves
Heating
Electrical Currents
Mechanical.
The Law of Conservation of Energy
Energy can be stored and changed (transformed) from one for to another but it can never be made or destroyed.
Calculating Energy Efficiency
Def- How much of the total energy is transferred into useful energy.
Efficiency= useful energy output / total energy input x 100
Work Done
Def- any transfer of energy. Can be called 'energy transferred' or just 'work'
Factors that effect energy transferred- - The distance through which the force causes the body to move in the direction of force. - The size of force acting on the object.
work done (J) = force (N) x distance moved (Meters)
Gravitational Potential Energy
Mass, Height and strength of gravity affect gravitational potential energy.
9.8 N/kg is earths gravitational field strength.
GPE= m x g x h or Ep= weight x h
m= mass (kg)
GPE/Ep= gravitational potential energy.
g= gravitational field strength (N/kg)
h= height (m)
Kinetic Energy
Ek= 1/2 x m x v²
Ek= kinetic energy (J)
m= mass (kg)
v= velocity (m/s)
Kinetic energy depends on mass and velocity
velocity= distance/ time
Power
Def- The energy transferred per second (in watts).
Power (W) = Energy (J) / Time (s)
W= J/s
mW → W (divide by 1000)
kJ → J (x 1000)
