Studied by 2 people
mechanics & thermal energy
Momentum formula and unit
p=mv and kgm/s
Impluse formula and unit
∆p=Ft and Ns
Kinetic energy formula and unit
KE = ½ mv 2 and J or kgm 2 /s 2
Potential energy formula and unit
PE =mgh and J
Work Formula and unit
W=Fd and J or Nm
Power formula and unit
power=W/t and Watts or J/s
Energy efficiency formula and unit
( useful energy / total energy ) x 100%
What is momentum ?
how hard is it to stop an an object from continuing moving
What is impluse ?
the change in momentum on a given time
Conservation of Momentum
momentum is conserved before and after the collision
Elastic collisions
object collied and bounce of each other
Inelastic collisions
when objects collide and stick together
Explosions
when objects start at rest and then “explode” away from each other
Energy
the ability to cause a change
Types of energy
Kinetic : Mechanical, Sound, Electric,Thermal, Radiant
Potential : Gravitational, Elastic, Chemical, Nuclear
Kinetic Energy
energy caused by movement
Gravitational Potential Energy
the energy stored in an object, but by height
Conservation of Energy
energy cannot be created or destroyed it can only be change from one to another
Work
a force is applied to an object to make it move
Power
how much work is done per unit of time.
Energy Efficiency
energy transfers are never 100% efficient
it is the percentage of energy you are able to get that is useful
Thermal Energy
total energy of ALL the particles in an object
temperature:
average kinetic energy of the particles in ONE location
Heat
movement of thermal energy from a warm to cold location
Three Methods of Heat Transfer
Conduction, Convection, Radiation
Radiation
transfer of thermal energy through ELECTROMAGNETIC WAVES (light).
Conduction
The transfer of thermal energy by PHYSICAL CONTACT
Conductors
materials that are good at conducting heats (metals)
Insulators
materials bad at conducting heat ( gases, plastic )
Convection
the transfer of thermal energy by the movement of a hot gas or liquid.
Note 
Flashcard (37)