LucidSTEM
IGCSE 0625 · MECHANICS · 1.7
Energy, work & power
Energy stores and conservation, kinetic and potential energy, work, power, efficiency, and energy resources. It builds on mass and forces and links to the transfer of thermal energy.
TOPIC 1.7: ENERGY, WORK AND POWER
CAMBRIDGE IGCSE PHYSICS 0625 · PATHWAYS
TheLucidSTEM · thelucidstem.com
BUILDS ON
1.3
Mass & weight
1.5
Forces
LEADS TO
2.3
Thermal energy
Efficiency
ENERGY
WORK · POWER
1 · STORES & CONSERVATION
Energy is stored and transferred, never made
or destroyed.
Stores include kinetic, gravitational, elastic,
chemical, thermal, and nuclear.
In any change the total energy stays the same.
It often spreads out and becomes less useful.
2 · KINETIC & POTENTIAL
EXTENDED
Moving and lifted objects store energy.
KE = ½ m v²
ΔPE = m g Δh
high: GPE
low: fast, KE
3 · WORK & POWER
Work is the energy transferred by a force.
W = F d
force × distance
Power is how fast energy is transferred.
P = W / t = ΔE / t
Energy in joules (J); power in watts (W).
4 · EFFICIENCY & RESOURCES
Efficiency compares useful output with the
total energy put in.
efficiency = useful ÷ total
input
useful output
wasted as heat
Resources: fossil fuels and nuclear, plus renewables
like solar, wind, hydro, and geothermal.
TOPIC 1.7: ENERGY, WORK AND POWER
CAMBRIDGE IGCSE PHYSICS 0625 · PATHWAYS
TheLucidSTEM · thelucidstem.com
BUILDS ON
1.3
Mass & weight
1.5
Forces
LEADS TO
2.3
Thermal energy
Efficiency
ENERGY
WORK · POWER
1 · STORES & CONSERVATION
Energy is stored and transferred, never made
or destroyed.
Stores include kinetic, gravitational, elastic,
chemical, thermal, and nuclear.
In any change the total energy stays the same.
It often spreads out and becomes less useful.
2 · KINETIC & POTENTIAL
EXTENDED
Moving and lifted objects store energy.
KE = ½ m v²
ΔPE = m g Δh
high: GPE
low: fast, KE
3 · WORK & POWER
Work is the energy transferred by a force.
W = F d
force × distance
Power is how fast energy is transferred.
P = W / t = ΔE / t
Energy in joules (J); power in watts (W).
4 · EFFICIENCY & RESOURCES
Efficiency compares useful output with the
total energy put in.
efficiency = useful ÷ total
input
useful output
wasted as heat
Resources: fossil fuels and nuclear, plus renewables
like solar, wind, hydro, and geothermal.