How do simple machines change the direction of force?

1 Answer
Jul 8, 2018


Simple machines use a pivot point to modify the magnitude and/or direction of a force.


Forces are vector quantities so they combine as vectors.

Simple machines use a pivot point such as a lever fulcrum or axle bearing to provide a "counteractive" force to combine with the applied force(s) to produce a resultant force, acting in a different direction and/or with a different magnitude to that applied.

The forces must comply with the rules of Newtonian physics,

i.e. if the forces are not in balance then something will be accelerating.

#W = F*d#
work = force * distance (= energy)

#power = "energy / time" #, etc.

For a lever in balance #F_1*L_1= F_2*L_2# :

Note that there must be a counteractive force acting upwards at the fulcrum if the lever is in balance

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Gears, wheels and pulleys use the same principles but allow continuous movement, whereas a lever has a limited range of movement.