p7.1 Flashcards
what voltage and frequency are mains at?
230V
and 50Hz
what are the 8 energy stores?
chemical thermal kinetic gravitational elastic nuclear electrostatic magnetic
what are the 4 ways energy can be transferred
mechanically (with forces)
electrically (with an electric current)
heating by particles
heating by radiation
equation to calculate how energy transferred mechanically?
work done = force x distance
equation to calculate how energy is transferred electrically?
energy transferred = power x time
equation for kinetic energy?
1/2 mv^2
what is another way of writing out 1N?
1 kg m/s^2
what is another way of writing out 1J?
1 Nm
in a car accelerating how does the energy store change?
more chemical store vs kinetic store
THEN
more kinetic store vs chemical store
what is the transfer between a braking car?
initially -
more in kinetic store than thermal store
final -
more in thermal store than kinetic store
WORK DONE BY BRAKES SLOW CAR DOWN kinetic -> thermal stores of break pad
equation to calculate energy/work in a spring
e = 1/2 kx^2
energy = 1/2 x spring constant x compression^2
how would energy stores change of a spring being compressed (due to a gymnast)?
initial - elastic low
kinetic + gravitational high
final - elastic high
kinetic - nothing
gravity = little
equation to calculate change in energy in gravitational store
e = mgh
energy = mass x gravitational field strength x change in height
