How is rotational motion converted into up and down motion in various motors and cars?
This is mechanical. There are two possibilities of rotational motion, it depends on its plane of rotation, whether it is vertical or horizontal. Case No. 1 If the rotational motion is on a vertical plane, meaning its axis of rotation is horizontal, the use of crank shaft is enough. Case No. 2 If the rotation is along a horizontal plane, you either use a “cam” and idler or first convert the axis of rotation to be horizontal by means of bevel gears then proceed as in Case no. 1 But it seems, your question is reversed.
