First Class LeverFulcrum is

between input force and the load

Always change the direction of the input force

:

ItemNumber of Class

1 Levers Used

see-saw

                     

a single class 1 lever

hammer's claws

                 a single class 1

lever

scissors                2 class 1 levers

pliers               2 class 1 levers

2nd Class LeverThe load is between

the fulcrum and the effort force

The direction of the input force is not changed

MA greater than one

But the force must be exerted over a greater distance

:

ItemNumber of

Class 2 Levers Used

stapler

                         

a single class 2 lever

bottle openera single class

2 lever

wheelbarrow

                         

a single class 2 lever

nail clippersTwo class 2

levers

nut crackerTwo class 2

levers

3rd Class LeverInput force is between

the fulcrum and the loadThey do not change the

direction of the input force

MA of less than oneOutput force is always

less than the input forceThe distance the output

force is exerted is increased

:

ItemNumber of

Class 3 Levers Used

fishing rod

                  

a single class 3 lever

tweezersTwo class 3

levers

tongs

                                 

Two class 3 levers

Pulleys

Pulley – moveable wheel with a groove for rope or chain to run through

Cranes, construction equipment, flagpoles, cars

2 reasons we use pulleys

Change a forces direction

To make work easier

Single PulleyChanges the

direction of the force

MA= 1Effort distance

equal to resistance distance

Single Moveable PulleyUsually one

stationary pulley and one moveable

MA= 2Effort distance

must be twice as long as resistance distance

Block and tackleSystem of fixed and

moveable pulley’s MA is equal to the

number of strands that support the load

MA = 4Effort distance is

four times longer than resistance distance

Other machinesWheel and axle- a

shaft or axle connected to a larger wheel that rotate together

Ex. Screwdriver, doorknob, faucets

IMA = radius of wheel radius of axle

Inclined PlaneInclined plane-

sloping surface that reduces the amount of force required to do work

Ex. RampsIMA= length of

slope height of slope

Inclined PlanesAn inclined plane

is a flat surface that is higher on one end

Inclined planes make the work of moving things easier

ScrewsScrew- inclined

plane wrapped around a cylinder

Ex. Jar lids, bolts, screws

WedgeWedge- inclined

plane with one or more sloping surfaces, changes the direction of the input force

Ex. ax, knife,

Compound machinesCompound machine-

several simple machines that operate together