7 — Energy Flashcards
Types of energy stores
Kinetic store, gravitational potential store, chemical potential store, elastic potential store, internal store, nuclear store
Define energy store
A way in which energy can be kept in a system
Work done
Work done by a constant force on a object is the product of the force and the distance moved by the object in the direction of an applied force
Define 1J based on work done
1J = work done by a force of one Newton, which moves an object thru a distance of one metre in the direction of the force
Gravitational potential energy store
G.p.e. Store is the energy possessed by a body due to its position relative to the ground
The principle of conservation of energy
The principle of conservation of energy States that energy cannot be created or destroyed. Energy can be transferred from one store to another. The total energy of an isolated system is constant.
Power
Power is defined as the rate of work done or rate of energy transferred.
Greater power -> greater amt of work done during same period of time/ Same amt of work done during shorter period of time
Renewable source of energy
Source of energy that can be replaced at a sustainable rate
Work done Answ technique
Yes/no work is done. Since a (direction)force is exerted on(x), and (x) moved (direction) in the same direction as exerted force, work is done.
Power rating
For every 1s, _J of electrical energy is converted to heat and light
Renewable energy sources
- Biofuels
- Wind
- Tides
- Hydropower
- Geothermal reservoirs
- Solar power
Non-renewable energy sources
- Fossil fuels
- Nuclear fuels
- Natural gas
Biofuels
- renewable energy source (RES)
- widely available on a large scale
- relatively cheap cost of production
Disadvantage:
- env pollution from gs produced
Wind
A:
- RES
- no GHG produced
D:
- intermittent power
- noise pollution + loss of habitat for wildlife -> land cleared to build turbines
Tides
A:
- RES
- more reliable than wind/sun
- no GHG produced
D:
- high cost of building tidal barrages, turbines n generators
- marine life affected due to alterations of water currents, noise n emission of electromagnetic fields
Ke water -> ke turbine
Hydropower
A:
- RES
- no GHG produced
Gpe water -> ke turbine
D:
- high cost
- posb dmg to env due to damming of river
Geothermal reservoirs
A:
- RES
- clean source of naturally available energy in internal stores
Ie water -> ke turbine
D:
- release of poisonous gases ->. Env pollution
-not widely available
Solar power
A:
- RES
-no GHG produced
D:
- weather-dependent
- solar panels takes up lots of space
Fossil fuels
A:
- independent on env factors, more reliable
- relatively cheaper cost of production
D:
- NRES
- gases produced during burning -> env pollution + GW
Nuclear fuels
- low carbon energy resource -> lower GHG emissions causing gw
- more reliable in supplying uninterrupted power
D:
- NRES’- risk of accidents + pollution from improper radioactive waste disposal
Natural gas
A:
- easy to store
- cheaper than other FF
- large reserves
- less pollution
- reliable
D:
- non-renewable
- reduce GHG
- danger of explosion
- danger of CO poisoning
Describe the pathway and energy transfer of the falling ball
Energy in gravitational potential store is transferred mechanically to kinetic store of the ball by weight of ball acting over distance it falls
Kinetic energy
Energy a body possessed due to its motion
Gravitational potential energy
Energy o a mass due to its position in a gravitational field
Efficiency
Ratio of useful energy output over the total energy input and is usually expressed as a percentage
Energy
Capacity to do work
One watt
Rate of work done or energy conversion of one joule per second
State one disadvantage of using wind turbines to produce a high proportion of the electricity in SG. [1]
It is not windy in Singapore / not enough space to build
Gravitational potential energy
Gpe is the energy stored in the object due to its vertical height above ground.
