P1:Energy Flashcards
what is a system
object or group of objects
what is the equation to find kenetic energy (J)
0.5 x mass(kg) x (speed,m/s)^2
what is the equation for elastic potential (J)
0.5 x spring constant(n/m) x (extension,m)^2
What is gravitational potential energy (J)
mass (kg)x gravitational field strength (n/kg) x height (m)
How to calculate a change in thermal energy (j)
mass (kg) x specific heat capacity (j/kg celsius) x temperature (celsius)
what is the required practical to test for specific heat capacity
1:place the beaker on top of balance and set it to zero
2:add oil to beaker and record the mass
3:put thermometer and immersion heater into the oil
4:read starting temperature and insulating foam
5:connect joulmeter to the immersion heater and connect power back to joulmeter
6:leave it for 30 min
7:read the total number of joules that pass through the immersion heater and read the final oil temperature
why might there be inaccuracies in the test for specific heat capacity
thermal energy passes out of the beaker, not all thermal energy passes into the oil, incorrect reading, thermal energy not being spread out
what are the 2 equations to find power (w)
energy transferred/time
work done(j)/time
what can energy only do
store or dissipated
what are the 2 equations for efficiency
useful output energy transfer/total input energy transfer
useful power output/total power input
how can we increase efficiency
insulation lubrication and streamlining
what is lubrication
a substance that reduces friction
what is streamlining
an object shaped to travel through air and water with little resistance
what is a renewable energy source
a resource that is being replenished as its used
what are the main sources of energy
fossil fuels, nuclear fuels, biofuels, hydroelectricity,geothermal , the tides, the sun, and water wave
