What determines the mechanical advantage of a screw?

The mechanical advantage of a screw is primarily determined by the distance between the threads, known as the pitch, and the length of the screw itself. The pitch indicates how tightly the threads are wound; a smaller pitch means that the threads are closer together, which allows the screw to lift a heavier load with less effort.

Additionally, the length of the screw plays a significant role in mechanical advantage. A longer screw typically provides a greater mechanical advantage, as it allows for a longer distance over which a user can apply a force. This effectively translates into less force needed to lift the same weight compared to shorter screws.

The other options do not directly affect mechanical advantage in the same way. The weight of the object being lifted is a factor in the overall dynamics but does not define how much mechanical advantage the screw provides. The speed of rotation is related to how quickly the screw can be used but does not change the fundamental ratio of input to output force. Lastly, while the angle of the screw (or the incline of the threads) can influence the ease of use, it ultimately ties back to pitch and thread design for calculating the mechanical advantage.