# Mechanical engineering

The physics of all three classes of lever are *vitally* critical to understand, and it's all based on the placement of the effort, fulcrum, and resistance:

1. Effort - Fulcrum - Resistance: The effort pushes downward and moves the resistance upward, and the mechanical advantage can be less or greater depending on the situation (e.g., see-saw).
2. Effort - Resistance - Fulcrum: the effort pushes upward to move the resistance upward, and the mechanical advantage is always greater (e.g., wheelbarrow).
3. Resistance - Effort, Fulcrum: the effort pushes upward to move the resistance upward, and the mechanical advantage is always lesser (e.g., tongs).

Most elaborate mechanical objects are simply derived off simple ones:

- A wheel is a circular, symmetrical object that maintains its form.
- A gear is a wheel with cut teeth meant to interlock with something else (usually other gears).
- A screw is an inclined plane around the perimeter of a standard nail.
- A rope or cable is a flexible cylindrical object, typical used to convey physical energy from one place to another.
- Pump assemblies migrate a liquid through a tube, typically from a mechanical or electrical signal.
- A belt is a flat object like a rope, typically made into a loop, typically designed to connect wheels together.
- A spring is made of metal specialized in tensile strength, where it reverts to its original form after being distorted.

Usually, the components can be *vastly* complex, but are activated by an individual signal. In a very complex system, those signals can cascade, where one interaction can create multiple signals sequentially to create the desired result.

These parts come together to create more advanced components:

- A pulley is a wheel with a belt or rope around it.
- A cogwheel or gearwheel adds little cogs around the outside of a wheel to make it interlock with other components more snugly than belts or wheels can provide.
  - For even tighter fits, a spline is the ridge or tooth that closely matches with a groove in a mating piece, typically to transfer torque.
- A worm gear is a cylindrical screw-shaped gear that magnifies torque to a standard gear.
- Chains are ropes, but with holes in the middle and typically made of metal. Linked chains tend to distribute weight, and single-assembly chains interlock very well with sprockets (which are basically cogwheels attached to chains).
- Servomotors activate mechanical motion from a signal (typically electrical).
- A shock is a sealed hydraulic mechanism that maintains a cushion of pressurized fluid (typically air) to absorb impacts.
- A transmission is a vast set of gears, chains, servomotors, and springs designed to apply the correct amount of torque and rotational energy relative to the engine and drivetrain/alternator.

Typically, these objects are assembled into complex patterns that magnify specific aspects:

- Using differently sized gearing can expand or contract the applied force over a certain amount of time, which can be used for either timing (e.g., a watch) or balancing forces (e.g., automotive transmission).
- Changing the angle of the force can dramatically improve how much energy can directly apply to something or diminish [breakdown](https://adequate.life/fix/).