Screw

Adam Bede and Steven Arterbery

Screw

A screw is simply a incline wrapped around a cylinder. Screws can do two things. They can convert a force that goes around and around into a force that goes up and down and they can also go into things like a metal bolt or wood to interlock things together so they don't come apart.

Examples of the Screw

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One example of a type of screw is an actual screw and that is used to hold things together. Some examples would be a screw holding a door knob to a door, a battery cover on a phone, and a fan attached to a ceiling.
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Another example of a type of screw is a jar. The inside of the jar lid has an incline on it and so does the outside of the top of the jar. This allows the jar lid to screw onto the jar.

Mechanical Advantage

The screw provides mechanical advantage by turning rotary motion into linear motion. A screw allows the energy required to drive the screw to be spread out over time rather than all at once. This can make the work seem easier. To calculate the mechanical advantage of a screw you need to find the circumference of the screw (diameter multiplied by Pi) and the pitch of its threading (length between the screw's thread). The length between the screw's threads is calculated by counting the number of threads in an inch then dividing it by the total number of threads. To get the mechanical advantage, divide the circumference by the pitch.

Example Problem

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