physics 1
what is the unit of energy?
joules
name a material that does not easily allow the transfer of thermal energy
insulator
what is the energy an object has because of its movement?
kinetic
what is the ratio of the useful energy output to the total energy input?
efficiency
name every energy store
magnetic, kinetic, heat (thermal), light, gravitational potential, chemical, sound, electric, elastic, nuclear
what is energy?
the ability of doing work
how do you work out work done?
work done= force x distance
name some examples of renewable energy
solar power, wind power, hydroelectric power, tidal power, wave power, geothermal power, biofuels
what is the equation linking kinetic energy, mass and speed?
kinetic energy= 1/2 x mass x (speed) squared
list some examples of objects with kinetic energy stores
toy car travelling down a ramp, gas particles moving in the air, parachute falling through the air
name the unrenewable energy sources
fossil fuels, nuclear fuel
what is the equation linking elastic potential energy, spring constant and extension?
elastic potential energy= 1/2 x spring constant x (extension) squared
what is the unit for spring constant?
newtons per metre (n/M)
what is the unit for extension?
metres
list some examples of objects with elastic potential energy stores
stretched elastic band, tennis ball that has been squashed, extended spring
what is the equation linking gravitational potential energy, mass, gravitational field strength and height?
gravitational potential energy= mass x gravitational field strength x height
what is the unit for gravitational field strength?
newtons per kilogram, N/kg
list some examples of objects that have gravitational potential energy stores
apple on a tree, plant pot on a windowsill, aeroplane in the sky
what is the equation linking change in thermal energy, mass, specific heat capacity and temperature change?
change in thermal energy= mass x specific heat capacity x temperature change
what is the unit for specific heat capacity?
joules per kilogram per degree celsius, J /kg degrees C
write a definition for specific heat capacity
the amount of energy needed to increase the temperature of a 1kg material by 1 degree celsius
name the useful energy transfers for a picture on a television screen
chemical energy stores -> thermal energy stores, and light and sound carry energy to the surroundings
name the energy dissipated to the surroundings for a picture on a television screen
thermal energy stores of the surroundings
name the useful energy transfers for a printer
chemical energy stores -> kinetic energy stores
name the energy dissipated to the surroundings for a printer
thermal energy stores and some is carried by sound waves to the surroundings
name the useful energy transfers for a mobile phone
chemical energy stores -> thermal energy stores and light and sound waves carry the energy to the surroundings
name the energy dissipated to the surroundings for a mobile phone
thermal energy stores of the surroundings
describe the energy store changes for a football that has been kicked upwards
as the ball moves upwards, the kinetic energy store of the ball decreases and the gravitational potential energy store of the ball increases
describe the energy store changes for a squash ball hitting a wall
when the ball hits the wall, kinetic energy decreases and elastic potential energy increases. some of the energy is also transferred to the surroundings. the thermal energy of the surroundings increases and some of the energy is carried by sound waves
describe the energy store changes for a car accelerating
as the car moves, the chemical energy of the petrol decreases and the kinetic energy of the car increases. some of the energy is also transferred by sound waves to the surroundings and the thermal energy store of the surroundings also increases
define renewable energy resources
a renewable energy resource can be replenished
define a non- renewable energy resource
a non- renewable energy resource will eventually run out
what happens when work is done?
a force moves an object and energy is transferred
what is force measured in?
newtons
how do you work out power?
power= work done/ time taken
what is chemical energy?
includes fuels, food or chemicals in batteries. the energy is transferred in chemical reactions
what is kinetic energy?
the energy an object has because it is moving
what is gravitational potential energy?
the energy stored in an object because of its position, such as an object above ground
what is elastic potential energy?
the energy stored in a springy object when you squash it
what is thermal energy?
the energy a substance has because of its temperature
what is magnetic energy?
the energy stored within a magnetic field
what is light energy?
a form of kinetic energy that travels in waves and can be detected by the human eye
what is sound energy?
a form of mechanical energy that travels as sound waves, resulting from the vibrations of an object
what is electric energy?
the energy transferred when electrical charges move across a potential difference