physics Flashcards
name all of the energy types
magnetic, kinetic, heat, light, gravitational potential, chemical, sound, elastic potential, electrical, nuclear
(most kids hate learning g c s e energy names)
what is the law of conservation of energy?
energy can be transferred or dissipated. it can not be created or destroyed.
what is work done?
work is defined as the amount of force needed to move an object a certain distance
it is measure of an energy transferred to or from an object which allows it to be moved
what’s the equation for work done?
w = f x s
w - work done ( J, joules or newton -metres, Nm)
f - force (N, newtons)
s - distance (metres,m)
what’s the equation for gravitational potential energy?
Ep = mgh
Ep - GPE
m - mass (kg)
g - gravitational field strength (9.8N/kg on earth)
h - height (m)
what’s the equation for kinetic energy?
Ek = 1/2mv^2
Ek - kinetic energy (joules J)
m - mass (kg)
v - velocity (m/s)
what’s the steps to follow when doing an equation?
- find variables
- choose equation
- check units
- substitute
what’s the relation between GPE and Ek
if an object goes straight up into the air Ek is converted to GPE
in science we assume that this energy transfer is 100% efficient
the opposite would be true for an object falling to the floor
F = ke
Force(N) = spring constant (Nm) x extension (m)
what’s the equation for elastic potential?
Ee = 1/2ke^2
Ee - elastic potential energy (J)
k - spring constant (Nm)
e - extension/ compression (m)
what is power?
power is the amount of energy transferred (work done) by an object per unit of time
what’s the equation for power?
power = energy/ time
power - watts (W)
energy - (J)
time (seconds, s)
what happens to the energy wasted in a lightbulb
it’s transferred to surroundings by heating
why is it useful to have both a wind turbine and a fossil fuel generator 2 reasons
sometimes there’s no wind
when there is wind less fuel is burned
what is a non renewable energy resource
an energy resource that can’t be replenished as it’s used
