Science - Physics Chapter 4: Energy: Simple Machines

Vocabulary flashcards covering simple and complex machines, lever classes, mechanical advantage, inclined planes, screws, wedges, wheel and axle systems, and pulleys.

Machine

A tool or device that makes our work easier.

Simple Machine

A basic mechanical device with few or no moving parts that makes work easier by changing the direction or strength of a force.

Complex Machine

A device (also called a compound machine) made up of two or more simple machines working together to perform a task.

Lever

A rigid rod that can turn freely around a fixed point of support.

Fulcrum (F)

The fixed point about which a lever rod turns freely.

Load (L)

The object that has to be lifted, cut, or moved using a machine.

Effort (E)

The force that one needs to apply on a machine to perform a task.

Load Arm (LA)

The distance of the fulcrum from the point at which the load acts.

Effort Arm (EA)

The distance of the fulcrum from the point at which the effort is applied.

Class-One Lever

A lever in which the fulcrum is located somewhere between the load and the effort (examples include seesaw, crowbar, claw hammer, scissors, pliers, nail cutter, and beam balance).

Class-Two Lever

A lever in which the load is located between the effort and the fulcrum (examples include bottle opener, nutcracker, and wheelbarrow).

Class-Three Lever

A lever in which the effort is located between the fulcrum and the load (examples include fishing rod, tongs, cricket bat, and tweezers).

Mechanical Advantage (MA)

The ratio of the load to the effort, calculated as $MA = \frac{\text{Load}}{\text{Effort}}$.

Principle of Lever

The rule stating that $\text{Load} \times \text{Length of load arm} = \text{Effort} \times \text{Length of effort arm}$, which means $MA = \frac{\text{Load}}{\text{Effort}} = \frac{\text{Length of effort arm}}{\text{Length of load arm}}$.

Mechanical Advantage of Class I Lever

Can be $MA = 1$ (when effort arm = load arm), $MA > 1$ (acts as a force multiplier when effort arm > load arm), or $MA < 1$ (acts as a speed multiplier when effort arm < load arm).

Mechanical Advantage of Class II Lever

Always $MA > 1$ because the effort arm is greater than the load arm, causing it to act as a force multiplier.

Mechanical Advantage of Class III Lever

Always $MA < 1$ because the effort arm is less than the load arm, causing it to act as a speed multiplier.

Inclined Plane

A flat, sloping surface with one end higher than the other (examples include hospital ramps and wooden planks for loading trucks).

Screw

An inclined plane wound into a spiral around a straight rod that works with rotating movement to turn rotational motion into vertical motion.

Wedge

A set of two inclined planes that meet at a sharp or pointed edge, used to hold things together or cut/split things.

Wheel and Axle

An arrangement of a wheel (which has a larger diameter) rigidly attached to a rod called an axle (which has a smaller diameter).

Pulley

A simple machine made of a wheel with a groove around its rim and a rope passing through the groove that makes work easier by changing the direction of applied force.

Fixed Pulley

A pulley in which the axis of rotation is fixed, which changes the direction of the applied force.

Movable Pulley

A pulley in which the axle is free to move, which multiplies the applied force as a force multiplier.