P1 - Energy Flashcards
Examples of energy transfers
Kinetic, Sound, Light, Heating, Forces (mechanical)
Examples of energy stores
Gravitational potential, nuclear potential, thermal, magnetic potential, chemical, elastic potential
Describe energy transfer of a hamster running on a wheel to turn on a light bulb
Chemical -> Kinetic -> Electrical -> Light
Describe energy transfer of a wind turbine
Kinetic -> Electrical
State the Law of Conservation of Energy
Energy cannot be created or destroyed, only transferred from one type to another. (Input energy = output energy)
What is useful and wasted energy?
Useful energy is what we want out of the device, wasted energy is everything else that is made.
State useful and wasted energy of a TV
Useful - light, sound
Wasted - heat
State useful and wasted energy of a drill
Useful - kinetic
Wasted - heat, sound, some kinetic (vibrations)
What is energy efficency?
A measure of how good a device is at charging energy from one form to another.
State energy efficiency equation
Energy efficiency (%) = useful energy output (J) / total energy output (J) x 100
What is work?
Amount of energy transferred when a force moves in the direction of the force.
State work done equation
Work done (J) = force (N) x distance (m)
What is power?
Amount of energy transferred per second
State power equation
Power (W) = Energy transferred (J) / time (s)
What is kinetic energy?
A type of energy that is in anything that is moving.
