Work, Energy, and Simple Machines Vocabulary Flashcards

Vocabulary flashcards covering fundamental definitions, types, formulas, and concepts of work, energy, power, and simple machines.

Work

The measure of energy transfer occurring when a force acts on a body and causes a displacement in the direction of the force, represented by $W = FS\text{cos}(\theta)$.

Positive Work Done

Work done when the direction of force and displacement are the same, where the angle $\theta < 90^\text{o}$ (acute angle), which increases the speed of the body.

Negative Work Done

Work done when an object gets displaced in the opposite direction of the applied force, where the angle $\theta > 90^\text{o}$ (obtuse angle), which decreases the speed of the body.

Zero Work Done

Work done when the direction of force is perpendicular to displacement ($\theta = 90^\text{o}$) or when no displacement occurs ($S = 0$).

1 Joule of Work

The amount of work done when a force of $1\text{N}$ displaces an object by $1\text{m}$ in the direction of the force ($1\text{J} = 1\text{N} \times 1\text{m}$).

Energy

The ability to do work, measured in the same unit as work, which is the Joule ($\text{J}$).

Potential Energy

The energy possessed by a body due to a change in its position or shape.

Gravitational Potential Energy

The potential energy possessed by a body by virtue of its height, given by the expression $PE = mgh$.

Elastic Potential Energy

The potential energy possessed by a body by virtue of its shape and configuration, such as in a stretched spring or rubber band.

Work-Energy Theorem

The theorem stating that the work done on an object is equal to the change in its energy.

Kinetic Energy

The energy possessed by an object due to its motion, calculated as $KE = \frac{1}{2}mv^2$.

Mechanical Energy

The total sum of potential energy ($PE$) and kinetic energy ($KE$) of an object ($ME = PE + KE$).

Transformation of Energy

The process of converting energy from one form into another form.

Law of Conservation of Energy

The law stating that energy can neither be created nor destroyed, but can only be transferred from one form to another such that the total energy of a system remains conserved.

Power

The rate of doing work, defined as work done per unit time ($P = \frac{W}{t}$) or the rate of transferring energy.

1 Watt

The power of a body if it performs $1\text{J}$ of work in $1\text{s}$ ($1\text{W} = \frac{1\text{J}}{1\text{s}}$).

Horsepower

A unit of measurement for the power of an engine, equal to $746\text{W}$.

Simple Machine

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

Effort

The force applied to a machine to accomplish work.

Load

The force or resistance that needs to be overcome by a machine.

Mechanical Advantage

A value describing how a machine changes the magnitude of applied force, given as the ratio of load to effort ($MA = \frac{\text{Load}}{\text{Effort}}$).

Pulley

A simple machine made up of a grooved wheel and a rope that helps lift heavy loads easily.

Fixed Pulley

A pulley where pulling the rope downward moves the load upward, making the task easier solely by changing the direction of effort, with a mechanical advantage of $1$.

Inclined Plane

A flat, sloped surface connecting a lower level to a higher level to help lift heavy objects using less force.

Lever

A rigid bar that rotates around a fixed point (fulcrum) to help lift or move heavy loads with less effort.

Fulcrum

The fixed pivot point around which a lever rotates.

Class I Lever

A class of lever in which the fulcrum is situated in between the load and the effort (e.g., scissors, pliers, crowbars).

Class II Lever

A class of lever in which the load is situated in between the fulcrum and the effort (e.g., wheelbarrow, lemon squeezer).

Class III Lever

A class of lever in which the effort is applied in between the fulcrum and the load (e.g., tongs, tweezers, broom).