Changes in energy 2.0 Flashcards
describe the changes (in energy) in a swinging pirate ship ride at a theme park:
- at lowest and highest point of swing
lowest:
- maximum kinetic energy
- minimum gravitational potential energy
highest:
- minimum kinetic energy
- maximum gravitational potential energy
describe the changes (in energy) in a boat being accelerated by the force of the engine: (2)
- boat loses chemical energy as fuel is burned
- boat gains kinetic energy as it gains speed
describe the changes (in energy) in bringing water to a boil in an electric kettle: (2)
- electrical work is done as electricity (through electrical current) through the kettle increases the internal (thermal) energy of the metal
- which in turn increases the internal energy of the water which increases the temperature of the water
what do boxes and arrows in transfer diagrams represent? (2)
boxes = energy stores arrows = energy transfers.
what do sankey diagrams start off as? what do they split into?
-what does this show?
- start off as one arrow that splits into two or more points.
- shows how all the energy in a system is transferred into different stores.
when are sankey diagrams useful?
when the amount of energy in each of the energy sources is known
what is the width of the arrow drawn to? why?
- scale
- to show the amount of energy
what is the law of conservation of enegy?
energy can neither be created nor destroyed; it can only be transferred from one store to another
why does not all the gravitational potential energy of a falling object get transferred into kinetic energy?
as some work is done pushing against the air particles, some of the gravitational potential energy is transferred to the air particles and is stored as internal energy.
equation for calculating changes in gravitational potential energy:
GPE (J) = Mass (kg) x Gravitational Field Strength (N/kg) x (vertical) Height (m)
GPE = mxgxh
equation for calculating changes in kinetic energy:
KE (J) = 1/2 x Mass (kg) x Velocity (m/s)
