General Physics: Units, Vectors, Mechanics, and Dynamics

Vocabulary practice flashcards covering fundamental physical units, derived units, vectors, Newton's laws of motion, work, energy, friction, and collision dynamics based on the lecture notes.

Kilogram

The standard unit of mass.

Meter

The distance light travels in a vacuum in $1/299{,}792{,}458\text{ second}$.

Joule

The SI unit of work, equivalent to a newton-meter ($\text{N}\text{-}\text{m}$).

Watt

The SI unit of power, equivalent to a newton-meter per second ($\text{N}\text{-}\text{m/s}$).

Kelvin

The SI unit of temperature.

Candela

The SI unit of luminous intensity, equivalent to $\text{lumen/steradian}$.

Relative Intensity

A physical quantity that has no units (unitless).

Pascal (Pa)

The SI unit of pressure, equivalent to $\text{N/m}^2$.

Bar

A unit of pressure equivalent to $100{,}000\text{ Pascals}$.

Intensity

A physical quantity with the SI unit of $\text{watt/m}^2$.

Volt

The unit of potential difference, equivalent to $\text{joule/coulomb}$.

Electron Volt

The energy required by an electron that has been accelerated by a potential difference of $1\text{ volt}$, equivalent to $1.6 \times 10^{-19}\text{ joules}$.

Farad

The unit of capacitance, equivalent to $\text{coulomb/volt}$.

Ampere

The unit of electric current, equivalent to $\text{coulomb/second}$.

Ohm

The unit of resistance, equivalent to $\text{volt/ampere}$.

Lumen

The unit of luminous flux.

Luminous Efficiency

A property measured in the unit $\text{lumen/watt}$.

Lux

The unit of illumination, equivalent to $\text{lumen/m}^2$.

Footcandle

A unit of illumination equivalent to $\text{lumen/ft}^2$.

Newton

A unit of force equivalent to $100{,}000\text{ dynes}$.

Quantum

An elemental unit of energy.

Slug

An English unit of mass defined as the mass that is accelerated at the rate of one foot per second when acted on by a force of one pound; $1\text{ slug}$ equals $14.6\text{ kilograms}$.

Horsepower

A unit of power equivalent to $746\text{ watts}$.

Kilowatt-hour

A unit of work or energy.

Mole

An SI base unit that measures the amount of substance.

Decibel

The unit used to measure sound intensity.

Unit Vector

A vector with a magnitude of one and with no unit, whose purpose is to describe the direction in space.

Dot Product

Another term for the scalar product of two vectors; for two perpendicular vectors, it is always equal to $0$.

Cross Product

Another term for the vector product of two vectors; it is always equal to $0$ for two parallel or antiparallel vectors, or for any vector with itself.

Scalar Quantities

Physical quantities that are completely specified by just a number and a unit, or physical quantities that have magnitudes only (e.g., time).

Vector Quantities

Physical quantities that have both a magnitude and a direction (e.g., displacement, velocity, acceleration).

Vector

An arrowed line whose length is proportional to the magnitude of some vector quantity and whose direction is that of the quantity.

Vector Diagram

A scaled drawing of the various forces, velocities, or other vector quantities involved in the motion of a body.

Average Speed

The distance covered by a moving object in a time interval divided by the time interval.

Acceleration

The rate at which velocity changes with time.

Work-Energy Theorem

The principle stating that the work done by the net force on a particle equals the change in the particle's kinetic energy.

Kinetic Energy

The energy an object possesses by virtue of its motion, equal to the total work that particle can do in the process of being brought to rest.

Work

The physical quantity defined as the product of force and displacement.

Power

The time rate at which work is done.

Force

Any influence that can change the velocity of an object.

Mass

A measure of the inertia of an object.

Inertia

The property of matter which is the reluctance to change its state of rest or of uniform motion.

First Law of Motion

The principle that if no net force acts on it, an object at rest will remain at rest and an object in motion will remain in motion at constant velocity.

Second Law of Motion

The principle stating that the net force acting on an object equals the product of the mass and the acceleration of the object, with the direction of the force being the same as that of the acceleration.

Third Law of Motion

The principle stating that when an object exerts a force on another object, the second object exerts on the first a force of the same magnitude but in the opposite direction.

Weight

The force with which the earth attracts an object.

Friction

An actual force that arises to oppose relative motion between contracting surfaces.

Static Friction

The force between two stationary surfaces in contact that prevents motion between them.

Starting Friction

The maximum value of static friction.

Sliding Friction

Another term for kinetic friction, which is always less than static friction.

Efficiency of a Machine

The ratio of power output to power input.

Rest Energy

The energy something possesses by virtue of its mass.

Potential Energy

The energy something possesses by virtue of its position.

Elastic Collision

A collision in which kinetic energy is conserved and the coefficient of restitution equals $1$.

Completely Inelastic Collision

A collision where the two colliding objects stick together after impact, kinetic energy is lost to maximum value, and the coefficient of restitution is $0$.

Coefficient of Restitution

The ratio of relative speed after collision to relative speed before collision, which always applies jointly to the colliding objects.

Law of Conservation of Momentum

The principle stating that when the vector sum of the external forces acting on a system of particles equals zero, the total linear momentum of the system remains constant.

Impulse

The product of the force and the time during which a force acts.

Momentum

The physical quantity defined as the product of velocity and mass.