Physics 25-26 Flashcards
A set of interconnected parts
Systems
A system that exchanges both matter and energy with its surroundings
Open System
A system that can not exchange energy with its surroundings
Closed System
A system that can not exchange matter but can exchange energy with it’s surroundings
Isolated System
The total energy, including heat, in a system and it’s surroundings stays constant whenever heat is added to the system, it transforms into an equal amount of some other form of energy
The First Law of Thermodynamics
heat added to a system =
Mechanic energy + heat
Heat always flows natural from hot to cold
The Second Law of Thermodynamics
A machine that doesn’t lose any energy heat. The energy input will equal energy output. This is impossible
Perfect Machine
A device that converts heat into mechanical energy only some energy can be converted, the rest is expelled as exhaust
Heat Engine
A device that transfers mechanical energy into heat
Heat Pump
The first machine to use “hidden energy” was
Hero’s steam engine
In the 1600s people started
using coal
The demand for coal fuelled the need to come up with
more sophisticated machines
The gun power engine how does it work
gas is generated by an explosion inside the engine drove by a piston forward into a cylinder
Drawback of a gun power engine is
hazard of explosions, the piston could not be pulled back
The heat engine how does it work
Two hollow hemisphere’s are fitted together to create a vacuum by extracting the air through a valve water increases it’s size by 1300x when heated into steam. This would use heat to create steam to do work
Patented a steam engine
Thomas Newcomen 1712
Made the first heat engine
Denis Papin 1690
Designed a more efficient steam engine
James Watt 1763
powder engine
Chrisitan Igens 1698
Patented an engine fuelled by oil and gas
Robert Steete 1794
Invented the first internal combustion engine
Eugene Lebon 1801
Invented first steam powdered pump
Thomas Very 1698
Improvements made to Lebons design
1801-1867
designed an internal combustions engine that used gas
G. Daimier 1883
Cars and combustion engines in mass production
1890
Developed the 4 stroke internal combustion engine
N.A Otto and Eugene Lebon 1867
The initial energy source
energy input
The desired energy needed to do
Useful Energy Output
The work machines are suppose to do
Useful Work Output
A measured unit of how effectively a machine converts energy input into useful energy
Efficiency
E =
Useful mechanical energy/ total mechanical energy
Discovered that the transformation of heat into mechanical energy flows from a hot object to a cold object (some heat is loss in the process) also determined the laws of heat efficiency of heat engines
Sodi Carnot
He said that heat is another form of energy
James Prescott Jules
When an object may store energy because of its position relative to some other object it has the potential to close work
Potential Energy
When a force is applied against gravity, resulting in energy being stored. The energy stored in an object at any position above the earth
Gravitational Potential Energy
