What happens when there are energy transfers in a closed system?
There is no net change to the total energy in the system
How can energy in a system be changed?
Through work done by forces, in electrical equipment, in heating
Energy transferred is equal to…
Work done
Formula for work done
E=f x d
Energy=force x distance
Formula For GPE
GPE=mass x gravitational field strength x height
Formula for KE
KE=1/2 x mass x velocity²
How is energy dissipated?
Usually as thermal energy to the surroundings
When do mechanical processes become wasteful?
When they cause a rise in temperature, so energy dissipates by heating the surroundings
Formula for power
Power=energy/temperature
What is a watt?
Joules per second
Formula for effiency
Efficiency=useful energy/total energy
What is power?
The rate at which energy is transferred