energy transfer and power. Flashcards
what can’t happen to energy?
be created or destroyed.
how can energy usually be transferrred?
stored or dissipated ( spread out to the surroundings.)
what is wasted energy caused by?
unwanted energy transfers.
how can unwanted energy transfers be reduced?
lubrication.
tightening any loose parts.
thermal insulation.
how can :lubrication: help reduce unwanted energy transfers?
reduces the friction that produces heat.
how can :tightening any loose parts: help reduce unwanted energy transfers?
prevents unwanted vibrations that wastes energy as sound.
how can :thermal insulation: help reduce unwanted energy transfers?
reduces heat loss.
what doesn’t a system always have to be and what else could it be?
single device.
whole bulding.
how does a building waste energy?
loses heat to the surroundings causing it to cool down.
what does the rate of cooling depend on?
thickness and thermal conductivity of the walls.
in the situation: an object projected upwards: what is the energy transfer?
kinetic energy.
(from initial movement of the object.)
to GPE.
( from it’s increase in height.)
in the situation: an object hitting an obstacle: what is the energy transfer?
kinetic energy.
(from the moving object.)
thermal and sound energy.
(when object hits the obstacle.)
in the situation: a car accelerating: what is the energy transfer?
chemical energy.
( in the fuel.)
kinetic energy.
(movement of the car.)
in the situation: a car braking: what is the energy transfer?
kinetic energy.
( movement of the car.)
thermal energy.
( friction from brakes.)
in the situation: water boiling in a kettle: what is the energy transfer?
electrical energy.
thermal.
