Lesson 5 energy transfers:pendulum Flashcards
what is thermal energy
the energy stored due to an objects temperature
what is the law of conservation of energy
energy can be transferred usefully, stored or dissipated but can never be created or destroyed
what is a system
an object or group of objects
what does friction cause
it causes energy to be transferred to thermal energy stores
what is a closed system
where no energy can enter or leave
how can we reduce unwanted energy transfers
by reducing friction
examples of reducing unwanted energy transfers via reducing friction
use a lubricant (eg oil on a fixed point) for pendulum
or by moving the air particles from around the pendulum
what is the pendulum connected with
a mass
a string
a fixed point
as the pendulum swings where is there friction
in the fixed point
there is also friction when the pendulum passes through where
air particles
what does friction cause
energy to be transferred to thermal energy
the fixed point and the air around the pendulum gradually what
get warmer
The stores of thermal energy in the pendulum are less useful meaning what
the energy is being dissipated (wasted)
the energy being dissipated, does what to the pendulum
causes the pendulum to gradually swing with less energy and eventually stop
