Energy dissipation Flashcards
What is a system?
A system is an object or group of objects.
What does energy dissipation mean?
- Energy dissipation is the transfer of energy stores into less useful ones (into the surrounding.)Known as “wasted” energy.
What 2 cateogries can the total energy after transfer be put in?
Total energy after transfer can be useful or wasted.
What is energy efficiency?
- Energy efficiency is how good a device is at transferring energy input to useful energy output.
What is infrared radiation?
- Infrared radiation is electromganetic (waves produced: magnetic and electric) radiation released from a hot object.
Explain the energy stores/ transfers in a pendulum.
- ) When it is at its highest, it is highest in gravitational potential energy.
- ) When you let go, it has kinetic energy.
- ) When it goes to the other side, its gravitational potential energy build up again.
- ) Some energy is dissipated as thermal energy into the surroundings (through heating pathway.)
How is energy dissipated in a mechanical system?
- Work is done against friction which causes heating, releasing wasted thermal energy.
How can you decrease thermal energy dissipation?
- Adding lubricants between surfaces reduces friction
- Use insulation
How is efficiency calculated?
Useful energy transferred/ total energy supplied x100
What is power?
Power is the rate at which energy is tranferred each second.
How is power calculated?
Energy transferred/ time taken
What is power measured in?
Power is measured in Watts (W)
How can efficiency be calculated with power?
Useful power transferred/ total power supplied x100
How can you increase the efficiency of heating water on a pan?
- Cover up pan using lid –> avoids thermal energy from escaping.
- Make sides of pan plastic.
- Use pan with larger base –> some parts of hob won’t be in contact with pan.
- Lots of energy heats the base and then pan instead –> put heating element in water (like in kettle.)
