conservation and dissipation of energy- CH1

law of conservation of energy

energy cannot be created or destroyed

closed system

where no energy transfers take place into or out of the system’s energy stores

work done=

force x distance

work

work is done on an object when a force makes the object move

change in gpe=

mass x gfs x change in height OR weight x change in height

gfs on earth

9\.8 n/kg

kinetic energy=

0\.5 x mass x speed ^2

elastic potential energy=

0\.5 x spring constant x extension ^2

useful energy

energy in the place we want an need

wasted energy

energy transferred where we don’t want, usually to the surroundings

efficiency=

useful output/ input energy