P1.1 - P1.7 Flashcards
9 energy stores and egs
elastic - STRETCHED elastic band
kinetic - moving car
chemical - batteries, petrol, food
thermal - hot drink
vibration (kinetic (+ gravitational)) - tuning fork
nuclear - radioactive aton, nuclear bomb, core of the sun
gravitational PE - ball on high shelf
electric - thunderstorm
magnetic - magnet
how can energy be transferred
mechanical work - a force moving an object through a distance
electrical work - charges moving due to a potential difference
heating - due to temperature difference caused electrically or by chemical reaction
radiation - energy transferred as a wave, eg light and infrared - light radiation and infrared radiation are emitted from the sun
falling object energy transfers
conservation of energy
energy cannot be created or destroyed.
bungee jumping energy transfers
work done
force x distance (= energy transferred)
what happens to work done when overcoming friction (+ example)
how much force is needed to lift an object at constant velocity
GPE formula
weight (m x g) x height
why does GPE increase when object moves up (and by how much)
KE formula
1/2 x mass x speed2
elastic PE formula (+ units)
hookes law
F = ke
useful vs wasted energy
energy transfered to where it is wanted in the way that it is wanted vs not that
what happens to wasted energy
dissipated (spread out) and stored in less useful ways
what eventually happens to all useful energy
transferred to thermal energy store of surroundings
what happens to energy as it spreads out
energy efficiency
improving energy efficiency
closed system
total energy doesnt change - no energy can escape or enter
exam question!
energy transfers when (you are) stretching a spring
your chemical -> spring’s elastic PE
