1.1 Energy Flashcards
1.1.1 Energy stores and systems
What are the types of energy stores?
Chemical: in food, fuel, electric batteries
Kinetic: in moving objects
GPE: in objects raised above a planet’s surface
EPE: in a stretched, compressed or twisted object
Internal/thermal: in any heated object
Magnetic: in any object with a magnetic field
Electrostatic: in electrostatic forces between charges
Nuclear: the forces acting between atomic nuclei
1.1.1 Energy stores and systems
What are the force pathways for energys to travel through?
Mechanically: when a force acts and an object moves
Electrically: when an electric current flows
Heating: a temperature difference between objects
Radiation: an electromagnetic waves or sound
1.1.2 Changes in energy
Formula for kinetic energy
with units
KE = 0.5 × mass × speed x speed
KE = joules
mass = kg
speed = m/s
speed squared
1.1.2 Changes in energy
Formula for elastic potential energy
with units
EPE = 0.5 x spring constant x extension x extension
EPE = joules
spring constant = N/m – newtons per metre
extension = m – metres
extension squared
1.1.2 Changes in energy
Formula for gravitational potential energy
with units
GPE = mass x gravitational field strength x height
GPE = joules
mass = kg
height = metres, m
1.1.3 Energy changes in systems
Formula for SHC
with units
change in thermal energy = mass × specific heat capacity
× temperature change
thermal energy = joules, J
mass = kg
SHC = J/kg °C
temp change = °C
the amount of energy required to raise the temperature of one kilogram of the substance by one degree Celsius.
1.1.4 Power
Formula for power
with units & definition
Power is defined as the rate at which energy is transferred or the rate at which work is done.
Power = energy transferred/time
Power = work done/time
power = watts, W
energy = J
time = seconds, s
work done = J
watt
An energy transfer of 1 joule per second is equal to a power of 1
