Active Physics Vocabulary List (2005)

Misc

accuracy: How close the measured value is to the standard or accepted value of that measurement.
centimeter: A unit of measure in the metric system of measurement equivalent to 1/100 of a meter or 0.3927 inch; abbreviated is cm.
controlled variable: An object or condition you want to remain constant when you carry out a scientific investigation.
g: A unit of mass.
m: A unit of length equal to 1 meter.
m/s: A unit of speed meters per second.
manipulated variable: Object or condition that you change on purpose to test your hypothesis.
mass: A measure of how much material something contains. This shouldn't be confused with weight, which is a measure of the force of gravity on an object.
meter: The standard unit of length in the SI system of measure that equals 39.37 inches.
responding variable: Object or condition that changes when you change the manipulated variable in a scientific investigation.
SI system: A complete system of units of measurement for scientists; fundamental quantities are length (meter) and mass (kilogram) and time (second) and electric current (ampere) and temperature (Kelvin) and amount of matter (mole) and luminous intensity (candela).
slope of graph: The mathematical result of the change in the y axis of a line divided by the corresponding change on the x axis.
sound: Mechanical energy vibrations transmitted as waves through a solid, liquid, or a gas that can be detected by the human ear.
speed: Distance traveled per unit time.
subsystem: A major part of a system which itself has the characteristics of a system.
system: Group of interacting, interrelated, or interdependent parts made up of matter and energy that form a complex whole.
thought experiment: An experiment that cannot be or is not carried out in practice; it is reasoned through by thought and intuition.

Chapter 2 Motion

acceleration: The rate at which an object's velocity changes with time. It involves a change in the speed (increase or decrease) OR direction OR both speed and direction.
centripetal force: The force making a motion is a circle possible, always directed to the center of the circle.
force: Push or pull that gives energy to an object, sometimes causing a change in the motion of the object.
frame of reference: Any system for specifying the precise location of objects in space.
friction: A force that resists motion between two objects in contact.
Heat: The transfer of energy from one object at a higher temperature to another object at a lower temperature.
inertia: The tendency of matter to remain at rest if at rest, or to remain in motion in a straight line if in motion.
kgm/s²: The base units that make up a Newton (a unit of force).
kinetic energy: The energy possessed by a moving object. = ½ mv².
m/s²: A unit of acceleration meters per second squared.
momentum: Mass times velocity; a quantity that determines the potential force that an object can impart to another object by collision.
motion: A change in the position or location of one thing with respect to another.
net force: Sum of all the forces acting on an object.
potential energy: Stored energy of a material, a result of its position in an electric, magnetic, or gravitational field. PE=mgh.
thermal energy: Energy in the form of heat - the total internal kinetic and potential energy of an object due to the random motion of its atoms and molecules.
unbalanced force: A force that is not countered by another force in the opposite direction.
vector: A measurement having both magnitude and direction. It may be represented as a directed line segment.
velocity: Rate of change of position or direction of an object.
weight: The force of gravity acting on a body, equal to the mass of the body multiplied by the acceleration of gravity.
work: The transfer of energy from one object or system to another by applying a force over a distance. The formula is (force) x (distance).

Chapter 3 Waves

amplitude: The height of the wave.
constructive interference: When waves align and the resulting wave has troughs and crests that are larger.
destructive interference: When waves align and the resulting wave has troughs and crests that are smaller.
electromagnetic waves: Radiation consisting of waves of energy sent through space and matter associated with electric and magnetic fields resulting from the acceleration of an electric charge (light, x-rays, microwaves, gamma rays, etc.).
frequency: The number of back-and-forth cycles per second, in a wave or wave-like process.
gravitational field: Field created by any object with mass, extending outward in all directions, which determines the influence of that object on all others.
hologram: Laser-generated image with three-dimensional properties.
longitudinal waves: A wave in which the individual particles of a medium vibrate back and forth in the direction in which the wave travels. Sound is this type of wave.
mechanical waves: Waves which travel through a medium - sound waves, water waves and waves in solid objects.
photovoltaic cell: An electronic device consisting of layers of semiconductor materials that is capable of converting light directly into electricity.
primary waves: P waves, or compression waves, are seismic body waves that shakes the ground back and forth in the same direction as the direction the wave is moving.
reflection: The change in direction (or return) of waves striking a surface.
refraction: Waves change direction as they pass from one medium to another.
secondary waves: S waves, are seismic body waves that shakes the ground back and forth perpendicular to the direction the waves are moving.
transverse waves: A wave in which the vibrations of the medium are perpendicular to the direction the wave is moving.
wave crest: The highest part of a wave. The curved tops or ridges of an oscillating wave.
wave interference: The superposition (overlapping) of two or more waves resulting in a new wave pattern.
wave medium: The material that can carry a mechanical wave.
wave period: The time for one wavelength to pass a point. The time for a wave to travel the distance of one wavelength. P= 1/frequency.
wave speed: The velocity of a traveling wave (distance traveled per time).
wave superposition: The addition of two or more waves to produce a new wave.
wave trough: The lowest part of a wave, between successive crests.
wave: A rhythmic disturbance that transfers energy from place to place.
wavelength: The distance measured from crest to crest of one complete wave or cycle.