P1 Flashcards
how can energy be stored
energy can be stored in a variety of different energy stores
what ways can energy be transferred
- heating
- waves
- an electric current
- a force when it moves an object
what happens when an object falls
when an object falls and gains speed its gravitational potential energy decreases and its kinetic energy store increases
what happens when a falling object hits the floor without bouncing back
- its kinetic energy store decreases
- some or all of its energy is transferred to its surroundings - the thermal energy store of the surroundings increases and energy is also transferred by sound waves
can energy be created or destroyed
no
what does the conservation of energy apply to
all energy changes
what is a closed system
a system in which no energy transfers take place out of or into the energy stores of the system
when is work done on an object
when a force makes the object move
what is work done equal to
work done = energy transferred
what is the work done equation
W = F s
- W = work done
- F = force
- s = distance moved along the line of action of the force
what happens when work is done to overcome friction
work done to overcome friction is transferred as energy to the thermal energy stores of the object that rub together and to the surroundings
when does the gpe store of an object increase and decrease
the gravitational potential energy store of an object increases when it moves up and decreases when it moves down
what is the change in the gpe store of an object
change of gpe store (joules, J) = mass (kg) x gravitational field strength (N/kg) x change in height (m)
what does the kinetic energy store of a moving object depend on
- mass
- speed
what is the kinetic energy store of an object
E(k) = 1/2 m (v squared)
