Chapter 9 - Machines Flashcards
work
a force acting on something and moving it a distance
work =
force x distance
machine
any object that makes work easier
simple machines are
lever, pulley, wheel and axle, inclined plane, wedge, screw
lever
any bar that turns on a point
fulcrum
the point where the bar or lever turns
effort force
the force applied to a simple machine
resistance force
force that works against the effort
first class lever
The fulcrum is positioned between the effort and resistance
second class lever
The fulcrum is positioned at one end of the bar and the resistance is between the fulcrum and the effort
third class lever
The fulcrum is at one end of the bar and the effort is between the fulcrum and the resistance
types of pulleys
fixed pulley, movable pulley, block and tackle
fixed pulley
attached, does not move, changes the direction of the pull
moveable pulley
not attached, moves, reduces the amount of force needed to move an object, 1/2 force = twice distance
block and tackle
at least one fixed and one moveable pulley