P1-Energy Store and Transfers Flashcards
“Energy can be used up and created”(True or False)
False
Name the 7 stores of energy.
Kinetic energy, thermal energy, chemical energy, elastic potential energy, gravitational potential, magnetic energy, electrostatic energy
Name the 4 transfers of energy
Mechanical working, electrical working, heating by particles, heating by radiation
What equation should you use to work out “work done”
Force x Distance = Work Done
What units are used in this equation: force x distance = work done
(newtons) x (meters) = (Joules)
What is the n/kg of earth’s gravity?
9.8
(g for great = 9.8)
What equation do you use to work out the weight ?
Mass(kg) x gravity(N/kg) = Weight(n)
What is the equation for gravitational potential energy?
Gravitational potential energy (joules) = mass(kg) x gravitational field strength (N/kg) x height(m)
What is Gravitational potential energy (GPE)
It is the energy stored by an object by its position above the ground.
What is the equation for kinetic energy?
Kinetic energy = 1/2 (0.5) x mass(kg) x velocity squared (m/s)
how to find velocity?
distance(m)/time(s)
What happens to wasted energy?
Dissipated
What is the equation for efficiency?
Useful output/total output
Name 2 types of energy given out by a hair dryer
Thermal and kinetic energy
What is weight measured in
Neutons
What is distance measured in
Meters
What is work done measured in
Joules
What is the spring constant measured in?
N/m (newtons per meter)
What is extension measured in?
Meters
What is elastic potential energy
Energy stored in a spring object when you pull or squash it.
when is it mechanical working?
if it involves a force or surfaces being in contact (includes sound waves)
when is it electrical working?
if it is via current or if wires are involved
when is it heating by particles?
if it is heat moving from one place to another via conduction or convection
when is it heating by radiation?
if it is heat radiation or electromagnetic waves(light)
which energy transfers are being used:
1) rubbing hands together
2) burn fuel
1) kinetic——mechanical working—–> thermal
2) chemical—-heating by particles——>thermal
how might someone reduce unwanted energy transfers in a gearbox for a wind turbine?
you could add some oil to reduce friction between parts, as that could waste energy in the form of thermal energy.
what is the unit for gravity?
N/Kg
