Science - Mechanical Systems 1.5 and 1.6

Energy

the ability to do work

Work

an action done whenever a force causes an object to move

Kinetic energy

the energy of motion

Potential energy

stored energy

the law of conversion of energy

energy cannot be created or destroyed, only changed in form

friction

a force that resists movement, resulting in loss of energy through heat

efficiency

a value indicating how much energy is lost due to friction or heat, expressed as a percentage

E=

Wo/Wi x 100

Gears

rotating, wheel like objects with teeth cut ino the rim

Gear train

a group of gears

Parallel gears

driver and follower are the same size, MA=1

MA=1

Change of direction (MA)

Multiplying Gears

larger driver and smaller follower, MA<1

MA<1

Speed advantage (MA)

Reducing Gears

small driver and larger follower, MA>1

MA>1

Force advantage (MA)

MA=

\#teeth follower/#teeth driver

Speed ratio

the difference between the speeds of 2 gears

SR=1

Change of direction (SR)

SR<1

Force advantage (SR)

SR>1

Speed advantage (SR)

SR=

\#teeth driver/#teeth follower

Smaller gear

turns faster than larger gear

Larger Gear

turns slower than smaller gear