P1: Energy Flashcards
Name the different energy stores
Kinetic
Nuclear
Internal (thermal)
Gravitational potential
Elastic potential
Electrostatic
Magnetic
How is energy transferred
Mechanically: force moved object (work/doing something)
Electrically: when current flows
Heating: transfers from hot to cold objects
Radiation: light, sound, thermal radiation, transferred by rays or waves
Define kinetic energy
The energy stored in moving objects
What is the equation for kinetic energy?
Ek= 0.5 x m x v(squared)2
What to do to make J into kj?
divide by 1000
Define gravitational potential store
Why?
Energy stored in an object due to its position above earths surface
Due to force of gravity acting on an object
Equation for gravitational potential neeegy
Ep=m x g x h
(J) (Kg) (9.8) (metres)
Define elastic potential energy
Energy stored in stretched or compressed object
Equation for elastic potential energy
Ee= 0.5 x k x e2(squared)
Spring. Extension (m)
Constant
Or Ep= 1/2 x k x e2
How to change cm into m?
Divide by 100
What is a closed system
Systems were neither matter nor energy can leave, net change of energy
What is the unit for energy?
Joules
Define a system
A single, or group of objects
Explain thermal conductivity
The higher the thermal conductivity,
the higher the rate of energy transfer by conduction across material
Thermal conductivity in buildings
Rate of cooling is low if walls are thick and double glazed windows
If walls are thin metal sheets heat lost quickly .
