Work, energy and power Flashcards
Unit of measurement for energy
Joules (J)
Energy stores (6)
- kinetic
- gravitational potential
- elastic potential
- chemical potential
- internal store
- nuclear store
kinetic store formula
E = (mv^2)/2
Gravitational potential store formula
E = mgh
Energy transfers (4)
- mechanically
- by heating
- by propagation of waves (electromagnetic or mechanical waves)
- electrically
Mechanical energy transfer
force acting over a distance
energy transfer by heating
As a result of a temperature difference
Energy transfer by propagation of waves
- electromagnetic radiation (light)
- mechanical waves (two objects not in contact)
Energy transfer electrically
By charges moving through a potential difference
Conservation of energy (3)
- Total energy of a closed system is constant
- Energy can only be transferred from one store to another
- Energy cannot be created or destroyed
Define efficiency
Percentage of energy supplied to the object that is usually transferred
Define work done
The mechanical transfer to energy when a force is exerted an object and object moves a distances in the direction of the force
Unit mesurement of work
Joule (J)
1J of work done
1N moves 1m
Define power
Rate of energy transfer/work done per unit time
