Energy Flashcards
What makes object have energy?
object or substance has energy if it is capable of causing changes to itself or to other objects or substances. without energy nothing can happen- no changes can take place
Types of potential energy:
gravitational potential energy
chemical potential energy
strain/ elastic potential energy
Types of energy: (other than potential energy)
kinetic energy heat/ thermal energy light energy sound energy electrical energy
Potential energy:
‘stored’ or ‘hidden’ energy, can turn into ‘active’ energy under correct circumstances.
Gravitational potential energy: (Ep)
is energy due to the position of an object above a surface
e.g. boulder on a mountain
glass on table
Chemical potential energy:
object has chemical potential energy if it is capable of undergoing chemical reaction, turning into another substance and releasing ‘active’ energy.
e.g. sun
bottle acid
Strain/ elastic potential energy:
is energy stored in a stretched elastic or spring.
e.g. catapult
Kinetic energy: (Ek)
energy of movement 'active' energy is often associated with movement a moving body has kinetic energy e.g. vibrating piano string running cheetah
Thermal/ heat energy:
sometimes ‘active energy’ is thermal energy- heat energy
is the energy a substance body has due to the MOVEMENT OF ITS PARTICLES.
e.g. wood burned
cheetah running
what happens to the particles when there is no thermal energy?
what tempter does this happen at?
particles stop moving completely
absolute zero
-273 degrees on kelvin scale
Law of conservation of energy:
this important law states that energy can be neither created nor destroyed. It can, however, be TRANSFERRED to another body or TRANSFORMED (changed) into a different type of energy.
Factors influence gravitational potential energy:
the mass (m) of the object the vertical height (h) through which the object is lifted.
Gravitational Potential Energy Formula:
Ep=mgh
m= mass (kg)
g= gravity (N/kg) - 10
h= height (m)
work done= energy transferred= xJ
Reference point:
zero height position must first be assigned
usually ground is used zero position but table top can be used to as zero position, the work from table top.
variables that affect kinetic energy:
mass (m) of the object
speed (v) of the object
Kinetic energy formula:
Ek= 1/2 mv2 or
Ek=mv2/2
v= velocity or speed measured m/s= m.s-1 m= mass (kg)
relationship between kinetic energy and speed:
kinetic energy of an object is directly proportional to the square of its speed.
that means that doubling the speed will cause kinetic energy to increase by factor of four. cube speed = kinetic energy x 9
kinetic energy= J
1 Joule= 1kg.(m/s)2.
