Physics Unit 3 - Energy Flashcards
Gravitational energy
potential energy due to stored energy of an object’s height from a R.P
Potential energy
Stored energy by an object’s position, forces acting on it, object’s properties
Radiational energy
PE carried by light (electromagnetic waves)
Electrical energy
PE due to interaction of electric charges
Nuclear energy
PE stored in atomic nuclei (released by fission (Nuclear Power Plants) or fusion (Sun))
Elastic Energy
PE stored in a stretched/ compressed object
Thermal energy MOLECULES
Kinetic energy at molecular level- warmth from the vibrations of particles
Thermal energy PARTICLES
A measure of total energy of ALL the particles
Kinetic Energy
Large scale of object’s motion
Sound Energy
Kinetic energy due to wave-like vibrations of a particle through a medium
Chemical Energy
Energy stored in chemical bonds
Mechanical Energy
Kinetic Energy + Gravitational Potential Energy
Law of Conservation of Energy (2)
1) Energy cannot be created nor destroyed
2) When one energy is transferred to another, no energy is lost
Incandescent Light bulb
Eelec–(Bulb)–> Eth + Er
Arrow Shot Upwards
Ek–(pull arrow)–> Eelas —(bow firing)—-> Ek—-(arrow upwards)–> Eg —(Arrow falling)–> Ek (eventually Eth)
Flashlight
Ech-(battery)-> Eelec -(Bulb)-> Er + Eth
Candle
Ech-(chemical reaction)–> Eth + Er
Wind Turbine
Ek-(wind)-> Ek -(generator)-> Eelec
Solar Cell Calculator
En-(Sun)-> Er-(solar panel)-> Eelec
Hand Cranked Generator
Ek–(generator)->Eelec
Nuclear Fission Power Station
En-(Nuclear fission)-> Eth–(steam)-> Ek (generator)-> Eelec
Coal Fossil Fuel Power Station
Ech-(burning fuel)->Eth-(Steam)-> Ek-(generator)-> Eelec
Hydroelectric Power Station
Ek + Eg –(Falling water)-> Ek -(generator)-> Eelec
Kinetic Energy : If V^2 is doubled, what would Ek be?
Since Ek is directly proportional to V^2, when V^2 is doubled, Ek is 4x!
How much is 1 Joule worth?
E=Fap x d
1 J= N x m
What is positive energy? Does it gain or lose energy? What direction does Fap and displacement have to be?
Energy is transferred TO the object
Gains energy
Same directions
What is negative energy? Does it gain or lose energy? What direction does Fap and displacement have to be?
Energy is transferred FROM the object
Loses energy
Opposite directions
Formula for Work done with an Angle
W=(cos0 x fap) d
What is zero work?
Object’s energy does NOT change
Two causes for zero work (2) and give examples
1) Displacement=0
*No overall movement (pushing wall)
*No overall displacement (putting weights back after a workout)
2) Fap and d are perpendicular to each other (cos=90= 0) There is no change in Eg/Ek (ex. lifting shopping bags/ carrying back pack)
Power
Rate at which energy is transformed (how fast change happens)
How much a one Watts worth?
W=J/s
One watts = joules per second
What is the Kinetic Molecular Theory (KMT)
1)Matter is made up of particles that are in constant motion which gives them kinetic energy
2) Particles exert attractiveness and repulsive forces that keep them a certain distance apart giving particles potential energy
Temperature
The measure of average kinetic energy of the particles
Which one has a higher thermal energy? a) A small cup of hot chocolate or b) A big bucket of hot chocolate
B) b/c there are more particles which means more total Ek and Ep
Heat
Flow of thermal energy from an object of high temp. to low temp.
Which one is denser, cool or warm air?
Cool
Radiation
Transfer of energy through electromagnetic waves
What does radiation NOT require in order to take place?
A particle during transfer
How to prevent radiation
A reflective surface
Conduction
Transfer of energy through collisions of solid particles
How to prevent Conduction (2)
1) Remove particles (vacuum)
2) Thermal insulator (poor conductors)
Convection
Energy transfer through movement of particles in a fluid (liquid or solid)
Vertical movement of convection is called…
Convection current
How to prevent convection (2)
1) Remove particles (vacuum)
2) Thermal Insulator (poor conductors)
Specific Heat Capacity
The amount of energy required to increase the temperature of 1kg of a substance by 1C (degree)
What does the specific heat capacity depend on?
Material object is made of (its intermolecular forces)
Energy Conservation and thermal energy (principle of heat exchange)
Two substances of a different temperature are mixed, energy gained by the cooler object = the energy lost by the warmer object
Heat Curve
Shows temperature changes while a substance absorbs energy
Where is the energy used to separate the IMF particles of a substance
The environment
When using potential energy to change the state (liquid to solid) [freezing] of an object, what happens?
Epotential is released back into the environment and IMF bonds reform
When using potential energy to change the state (solid to liquid)[melting] of an object, what happens?
Energy from the environment is used to seperate particles by OVERCOMING IMF
Latent heat of fusion
amount of energy required to melt/freeze 1kg
Latent heat of vaporization
amount of energy required to vaporize / condense 1 kg
