Screw
A screw is a mechanism that converts rotational motion to linear motion, and a torque (rotational force) to a linear force.
Input force move a circle, Output force move one pitch.
`W_(i n) = W_(out)`
`F_(i n)(2πR) = F_(out)P`
`=>`
`F_(out)/F_(i n) = (2πR)/P = IMA`
IMA of Screw:
`IMA = (2πR)/P` or `IMA = (t h r e a d\ l e n g t h)/(screw\ l e ng th)`