Simple and Compound Machines Review

VOCABULARY flashcards covering definitions, lever classifications, and mechanical advantage principles for simple and compound machines.

Simple Machine

A device that allows work to be performed with less effort, typically with few or no moving parts, by changing force, distance, or the direction of the force.

Compound Machine

A device consisting of two or more simple machines working together to make work easier.

Lever

A rigid bar used to exert a pressure or sustain a weight by pivoting on its fulcrum.

Fulcrum

The pivot point on which a lever arm turns.

Lever Arm

The rigid bar component of a lever system.

1st Class Lever

A lever where the fulcrum is the middle component; it changes the direction of force, multiplies effort force, and magnifies speed and distance (e.g., seesaw, crowbar, scissors).

2nd Class Lever

A lever where the load ($R$) is the middle component; it multiplies effort force and always has a mechanical advantage greater than $1$ (e.g., bottle opener, boat oars, wheel barrow).

3rd Class Lever

A lever where the effort ($E$) is the middle component; it magnifies speed and distance but always has a mechanical advantage less than $1$ (e.g., baseball bat, golf club, broom, shovel).

Wheel & Axle

A simple machine where a wheel is fixed to a shaft called an axle; they move together as a simple lever to lift or move items by rolling.

Pulley

A grooved wheel around which a rope, belt, or chain passes, used to change the direction or magnitude of a force.

Fixed Pulley

A type of pulley that changes the direction of a force but does not create a mechanical advantage.

Movable Pulley

A pulley where the mechanical advantage is equal to the number of ropes that support it.

Combined Pulley

A pulley system where the effort needed to lift the load is less than half the weight of the load, with the disadvantage of traveling a very long distance.

Inclined Plane

A flat surface set at an angle or incline, such as a ramp, used to lift objects by pushing or pulling the load.

Wedge

A device that functions as a moving inclined plane, tapering to a thin edge; used for splitting or tightening.

Screw

An inclined plane wrapped around a cylinder forming a path and pitch; it changes rotary motion to linear force and acts as a threaded fastener.

Pitch

The distance between two threads on a screw.

Mechanical Advantage (MA)

A measure of how many times a machine multiplies the input force, calculated as $MA = \frac{F_o}{F_i}$ where $F_o$ is output force and $F_i$ is input force.

Ideal Mechanical Advantage (IMA)

The mechanical advantage of a machine without considering friction, calculated as $IMA = \frac{d_{in}}{d_{out}}$, where $d_{in}$ is input distance and $d_{out}$ is output distance.

Actual Mechanical Advantage (AMA)

The real-world mechanical advantage that accounts for friction, calculated as $AMA = \frac{F_{out}}{F_{in}}$.

Efficiency

A percentage showing how well a machine converts input work to output work, calculated as $\text{Efficiency} = \frac{AMA}{IMA} \times 100$%.

Work

The result of a force applied over a distance, expressed by the formula $W = Fd$.

Joule (J)

The unit of work, where $1\text{ Joule (J)} = 1\text{ Newton} \times \text{meter (Nm)}$.

Force and Distance Trade-Off

The principle that less force requires more distance and vice versa, defined by the equation $\text{Effort Force} \times \text{Effort Distance} = \text{Load Force} \times \text{Load Distance}$.