Conservation and dissipation of energy Flashcards
(20 cards)
define system
a object or groups of objects
how does energy change when an object is projected upwards
the kinetic energy will be transferred into gravitational potential energy
how does energy change when an object hits an obstacle
the kinetic energy will be transferred into thermal energy
how does energy change when an object is accelerated at a constant force
the stored energy source will be transferred into kinetic energy and gradually increase
how does energy change when a vehicle slows down
the kinetic energy store is transferred into a thermal energy store
how does energy change when bringing water to the boil
the chemical energy store decreases and the gravitational potential energy store increases
equation that links kinetic energy, mass and speed
kinetic energy = 0.5 x mass x speed(squared)
units and symbols for kinetic energy, mass and speed
kinetic energy : Ek joules
mass : m kilograms
speed : v meters per second
equation for elastic potential energy
elastic potential energy = 0.5 x spring constant x extention
units and symbols for elastic potential energy, spring constant and extention
elastic potential energy : U joules
spring constant : k N/m
extention : x meters
equation that links gpe, mass, height and gfs
gpe = mass x height x gfs
units and symbols for gpe, mass, height and gfs
gpe : U joules
mass : m kilograms
height : h meters
gfs: g N/m
equation that links power,energy and time
energy = power x time
units and symbols for power, energy and time
energy : e joules
power : p watts
time : t seconds
equation that links power, work done and time
power = work done / time
unit and symbols for power, work done and time
power : p watts
work done : W joules
time : t seconds
definition of power
the rate of transfer of energy
what is a watt
unit of electrical power
equation of efficiency
efficiency = energy output / energy input
ways to increase efficiency
Using more efficient devices and systems, such as LED lights and energy-efficient refrigerators
Reducing energy waste by turning off devices when they’re not in use Improving insulation in buildings to reduce heat loss
Using renewable energy sources, such as solar or wind power
