work, power and energy resources Flashcards
(7 cards)
1
Q
if a device is labelled 30 watts, what does it tell you about the energy transfer?
A
30w is the power rating
it tells you the rate of energy transfer - 30 j transferred per second
2
Q
what are the renewable resources of energy
A
- geothermal
- hydro electric
- waves
- tidal
- solar
3
Q
state the equation linking work done, force and distance
A
W = FD
4
Q
why does something lose gravitational potential energy when it falls
A
when it falls its height is reduced
this means the height of the centre of gravity is also reduced
5
Q
why are wind turbines not extremely abundant
A
- wind doesnt alwats blow
- visual pollution
- large sites are needed
- windy locations are needed
- building wind farms is expensive
6
Q
define kinetic energy
A
the amount of energy an object has as a result of its mass and speed
7
Q
define power
A
work done per unit of time
or energy per second
