Energy Flashcards
(18 cards)
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What are the main stores of energy?
Kinetic
gravitational potential
chemical
elastic potential
nuclear
internal
What energy store is food added to in your body?
chemical
What is the equation for kinetic energy?
0.5 x m x v^2
m=mass (kg)
v=velocity (m/s)
What is the equation for gravitational potential energy?
m x g x h
m=mass (kg)
g=field strength (N/kg 9.8)
h=height (m)
What is the equation for elastic potential energy?
0.5 x k x e^2
k=spring constant (N/m)
e=extension (m)
What is mechanical work?
energy transferred from one object to another
What is electrical work?
an electrical current transfers energy from one object to another
What is work done by heating?
Heating an object transfers energy to its internal store
What is work by waves?
light and other types of waves can transfer energy from one object to another
what is the law for mechanical work?
the work done by a force is equal to the energy transferred to the object
What is the equation for work done?
force x distance
Whats the equation for energy?
potential difference x current x time
what is the equation for electrical energy?
power x time
what is the equation for power?
work done/time
energy transferred/time
What is the equation for efficiency?
useful energy/total energy x 100
what are some examples of wasted energy?
wires - heat
car engines - noise and heat
friction - heat
How can you reduce friction?
lubrication
