Question

How do simple machines change the direction of force?

Answer 1

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

Explanation:

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,

`F=ma`
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

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