conservation of energy

Cards (7)

energy is neither created or destroyed, just changes between stores - it's still there
what is an open system
energy can go in and out (interaction with environment)
what is a closed system
when energy cannot go - it stays in (no interaction with environment)
why does the total energy in a closed system remain constant 
because energy cannot be created or destroyed
what is useful energy
the energy needed to do the job
what is wasted energy
the energy not needed
e.g. an object is going down a tall slide, what does it mean if it has less mass
because less mass = less gpe = less kinetic energy