P1 Flashcards
What are the eight energy stores?
Kinetic,
thermal,
chemical,
elastic potential
gravitational potential
electrostatic
magnetic
nuclear
What is the conservation of energy?
Energy can never be created or destroyed, just transferred from one form to another.
What is specific heat capacity?
The amount of energy needed to raise the temperature of 1 kg of a substance by one degrees Celsius
What is the definition of power?
The rate at which energy is transferred or the rate at which work is done
What is the unit of Power?
Watt(w)
What is a renewable energy resource?
An energy source, which can be replenished as it is being used up?
what is Kinetic energy
the energy stored in moving objects
stationary objects have no KE
how do we calculate KE
0.5xmassxspeed
what is elastic potential energy
the energy that is stored in a stretched spring
how is extension linked to force appilied
extension is directly proportional to force applied until the limit of proportionality
what is meant by gravitational potential energy
energy stored in an object due to its position above the earths surface
this is due to the force of gravity acting on an object
how do we calculate gravitational potential energy
mass x
gravitational field strength x
height
what is thermal energy
the energy stored in an object due to its temperature
what is a system
an object or group of objects
what is a closed system
no energy can enter or leave
what is the energy transfer like in a pendulum
-at the max height the mass has the most amount of GPE
-as the pendulum swings the GPE is transferred to KE
-the mass has the maximum amount of KE at the bottom of the swing
-As the mass swings back up the KE is transferred to GPE again
what does friction do as the pendulum swings
-friction causes energy to be transferred to thermal energy
-the fixed point and the air around the pendulum gradually get warmer
-thermal energy store is less useful and therefore energy is getting dissipated (wasted)
-the pendulum now swings with less energy and gradually stops
how do we reduce friction in a pendulum
-reduce air particles
-use lubricants
what happens to the energy stores during a bungee jump
-at the start all of the energy in the system is stored in GPE
-as the jumper falls energy is transferred from GPE to KE
-when the bungee rope starts to tighten,KE energy store is at its maximum
-when the rope is fully extended the KE is zero
-at this point all the energy is transferred to EPE
-bungee rope recoils,EPE is transferred to KE
-during the acend KE is transferred to GPE
-at the top of the acend all the energy is GPE
why does the bungee jumper never return to their original position
-energy is dissipated as thermal enrgy
-due to friction with air particles
-due to stretching effects with bungee rope
what is work done
whenever energy is transferred from one store to another
what is mechanical work
using a force to move an object
what is electrical work
current transferring energy
how do we calculate work done(j)
force x distance
what is the equation for power involving work done
work done/time
what is the equation for power involving energy transferred
energy transferred/time
what does efficiency tell us
tells us the fraction of the energy what we put into an appliance is transferred into useful energy
what is the equation for efficiency
useful power output/
total power input
what is the positives of using nuclear power to generate energy
-releases no carbon dioxide,does not contribute to climate change
-extremely reliable
how can we reduce loss of heat from buildings
-fill cavities with insulating materials with low thermal conductivity
-double glaze windows
-loft insulation with low thermal conductivity
what is the negatives of using nuclear power to generate energy
-contain highly dangerous radioactive materials,if released by accident it would be potentially disastrous
-decommissioning takes many years and is very expensive
why is the total positive charge in every atom of an element always the same
-positive charge is carried by protons
-every atom of the same element carry the same number of protons
how is heat lost through the walls of buildings
-energy is transferred through conduction
