CP3/8 Energy Flashcards
What is gravitational potential energy?
The energy stored from an object being high up
What is kinetic energy?
The energy of movement
What is meant by conservation of energy?
Energy cannot be created or destroyed. In a closed system energy transfers cause no net change to the total energy in the system.
What energy transfers take place when a ball is kicked up a hill?
KE from the foot is transferred to the ball then KE from the ball is transferred to GPE as the ball rolls up the hill.
What energy transfers take place when a car collides with a wall?
KE of the car is transferred to thermal energy in all the objects that have changed shape
What energy transfers are taking place when a car is accelerating>
chemical energy is transferred to kinetic energy
What energy transfers are taking place when a car is braking?
kinetic energy is transferred to thermal energy in the brakes
What energy changes are taking place when a kettle is boiling water?
electrical energy is transferred to thermal energy
How is energy wasted in mechanical processes?
Friction within the process causes some energy to be transferred to thermal energy which dissipates (spreads out) into the surroundings
How can we reduced wasted energy in mechanical processes?
Lubricating moving parts
What is efficiency?
What percentage of energy transferred is useful
List the 7 main energy sources available for use on earth
fossil fuels, nuclear fuel, bio-fuel, wind, hydroelectricity, the tides, the sun
What eventually happen to the energy when a car brakes and comes to a stop?
The energy turns into thermal energy which dissapates (spreads out into the surroundings).
List the three ways that the energy of a system can be changed
through work done by forces, in electrical equipment, in heating
What is the formula for work done?
Workdone = force x distance moved in the direction of the force
What is the unit for work done?
joules
What does work done mean?
energy transferred
Define power
the rate at which energy is transferred
What is the unit for power?
watt, W
What is one watt equivalent to?
1 joule per second
