Physics Terminology PDF

**Physics Terminology** ### **Unit 1: Kinematics (Chap 1-2)** Mechanics - the study of motion (the change is an object\'s location as measured by a particular observer) and forces Kinematics - focuses on the motion only without considering the cause Dynamics - focuses on the causes of the motion...

**Physics Terminology** ### **Unit 1: Kinematics (Chap 1-2)** Mechanics - the study of motion (the change is an object\'s location as measured by a particular observer) and forces Kinematics - focuses on the motion only without considering the cause Dynamics - focuses on the causes of the motion Scalar - a mathematical quantity that has magnitude (size) only. I.e. 25m Vector - a mathematical quantity that has both direction and magnitude. Represented by an arrow. I.e. 25m \[east\] Position - the distance and direction of an object from a reference point. Vector quantity Displacement - the change in position of an object. Vector quantity Distance - the total travel of an object, with no concern for direction. Scalar quantity Speed - the total distance traveled divided by the time elapsed. Scalar quantity Velocity - the total displacement divided by the time elapsed. Vector quantity Acceleration - how quickly an object\'s velocity changes over time (rate of change of velocity). a=change in velocity/change in time Uniform motion - motion at a constant velocity (speed and direction). Constant velocity. I.e driving down a highway with cruise control on Non-uniform velocity - motion with a changing velocity (speed or direction). Change in velocity. I.e pulling away from a stop sign Average speed or velocity - refers to the speed/velocity of an object over a time interval. Choose two point on the curve and determine the slope of this secant line Instantaneous speed or velocity - refers to the speed/velocity of an object at a specific instant time. Draw a tangent line (just touches the curve) at the time in the question Slope - gives acceleration during that time interval Area - used to figure out displacement Acceleration due to gravity (g) - refers to acceleration that occurs when an object is falling freely near the earth's surface. As a result it will experience an acceleration of 9.8 m/s2 \[down\] Terminal velocity - refers to the velocity an object reaches when the downward force of gravity is equal to the upward force of air resistance. Unless the surface area of the object changes, the velocity will remain constant Time of flight - the amount of time it takes for a projectile to complete its motion Range - the horizontal distance travelled by the projectile ### **Unit 2: Forces (Chap 3-4)** Newton\'s laws of motion - *First law - the law of inertia* - - - *Second law -* - - *Third law -* - Mass - refers to the amount of matter in an object is made of (kg) Weight - refers to the force of gravity acting on something (N) Gravity - is a fundamental force that binds the universe together Friction - caused by surface imperfections and is thus dependent on the materials in contact. microscopic "welds" form that must be broken to move the object Kinetic friction - Friction slowing down the motion of an object. Static friction - Friction preventing the motion of an object, increases up to a maximum (welds break) ### **Unit 3: Energy and society (Chap 5-7)** Matter - stuff that makes up the universe Energy - duel that makes matter go Power - the rate at which work is done Temperature - a measure of average kinetic friction energy of the particles in a substance Celsius - based on freezing point and boiling point of water Fahrenheit - based on the freezing and boiling point of salt water Heat - the flow of thermal energy from a warmer object to a colder one Specific heat capacity - the amount of thermal energy needed to increase the temperature of 1kg of a substance by 1\*C Latent Heat of Fusion (Lf) - The energy needed to melt 1.0kg of a solid. Latent Heat of Vaporization (Lv) - The energy needed to vaporize 1.0kg of a liquid. Nucleons - Particles in the nucleus (Protons and Neutrons) Proton - positive particle in the nucleus Neutron -neutral particle in the nucleus Ground state - state of an atom when all electrons are in their lowest energy levels Excited State - when one or more electrons are at higher energy levels Atomic number - \# of protons Atomic mass number - \# of nucleons in the nucleus Chemical symbol - Standard letter (s) used to represent an elements Isotope - an atom of an element that has the same number of protons but a different number of neutrons. This means that the atom will have a different mass as well Radioscope - an unstable isotope that has a nucleus that spontaneously changes structure. This releases energy (radiation) in the form of waves which can be harmful or beneficial Nuclear reactions - involves changes in the nuclei of atoms sometimes resulting in new elements (change in \# of protons) or transmissions Exothermic - releases energy Endothermic - absorbs energy Electrostatic force - the force of attraction or repulsion due to electric charges Strong nuclear force - the very strong force of attraction between nucleons (6 x 10\^39 times stronger than gravity) Half-life - the average length of time it takes a radioactive material to decay to half of its original length Nuclear fission -when an atom is caused to fragment by bombarding it with another particle. Decay - a spontaneous event where an unstable atom emits another particle. Fission - very heavy nuclei. Fusion - very light nuclei ### **Unit 4: Waves and sound (Chap 8-10)** Vibration - refers to the disturbance or cyclical motion of an object about an equilibrium point (ie. Pendulum, plucked guitar string). Waves are caused by the continuous vibration of a medium. Wave - is a travelling disturbance that transports energy from one place to another Mechanical Waves - waves that require a medium to travel. Energy is transferred due to vibrations of particles. Electromagnetic Wave - waves that can travel without a medium. (Originally created by charged particles, they are oscillations of electrical and magnetic fields.) Transverse Waves - waves that travel in a path that is perpendicular to the action that created the wave. (ie. Rope, water, "the wave") Longitudinal Waves - waves that move in a direction that is parallel to the action that created the wave (ie. Sound, slinky, etc) Wavelength (λ) -- the length of one cycle (in meters). Amplitude (A) -- the max disturbance from equilibrium (in meters). Period (T) -- the time for one complete cycle (in seconds). Frequency (f) - the number of cycles in a certain amount of time. If time is in seconds, frequency is in Hertz (Hz). Wave Speed (v) - the rate at which a wave is travelling through a medium. Sound Waves - Humans can hear sounds from 20 Hz to 20,000 Hz known as audible sound. Infrasonic sound - has frequencies below 20Hz (Earthquakes and Elephant communication). Ultrasonic sound - has frequencies above 20kHz (Dogs, bats, etc.). Mach Number - the ratio of airspeed of an object to the local speed of sound Supersonic - faster than or equal to the speed of sound. Subsonic - going slower than sound. Hypersonic - greater than or equal to 5 times the speed of sound. Interference - Sound waves move independently through a medium and through each other. Constructive interference- when the resultant wave has a larger amplitude because the two combining waves are in phase. Destructive interference - when the resultant wave has a smaller amplitude because the two combining waves are out of phase. Boundaries - when a wave encounters a new medium (wall, water, etc) it can be reflected (bounce back), transmitted (go through), and/or absorbed Standing waves - a result of reflections of waves with identical frequencies. The result is an interference pattern that seems stationary. Node -- the point on the standing wave that stays at rest. Antinode -- the point on a standing wave that moves the most. The amplitude is twice the original amplitude Internodal distance (dn) - the distance between consecutive nodes. This is equal to half of a wavelength Beats frequency - equal to the difference between the frequencies of the two interfering waves. Resonance - the tendency of something to vibrate with larger amplitudes when stimulated by its natural or resonant frequency (the frequency at which it vibrates most easily) *Mechanical* - the transfer of energy between objects due to physical contact. - - *Acoustical* - the transfer of energy due to sound waves. *Others* - Electrical (radios, tv tuners, etc) - - The doppler effect - the apparent change in the frequency of a wave caused by relative motion between the source of the wave and the observer Pitch - the frequency of the sound. Volume - the amplitude of the sound. Quality - the pleasantness or quality of the sound. Depends on the number of harmonics present. Resonator - (a hollow chamber) that helps improve loudness and quality by vibrating with the source. Free end system or open air column - the pattern for resonant lengths is similar to strings with Fixed ends. (ie. Xylophone, pipe flute) Fixed-Free end system or closed air column - the patterns are slightly different. (ie. Trumpet with a mute) Resonant lengths - the length of the air column (or string) is changing but the frequency stays the same Human ear - captures the energy of sound waves Pinna - collects sound waves and channels them into the ear canal (external auditory meatus), where the sound is amplified Auditory canal - collects sound waves and channels them into the ear canal (external auditory meatus), where the sound is amplified. Eardrum - separates the outer ear from the middle ear. The vibration of the eardrum causes movement of the three bones in the middle ear Eustachian tube - Balance pressure in the middle ear (commonly felt as your ears popping) Drain fluid from the middle ear Auditory nerve - chemicals rush into the cells, creating an electrical signal. The auditory nerve carries this electrical signal to the brain, which turns it into a sound that we recognize and understand Cochlea - a fluid-filled, spiral-shaped cavity found in the inner ear that plays a vital role in the sense of hearing and participates in the process of auditory transduction Stirrup - involved in the conduction of sound vibrations to the inner ear. (smallest bone in ear) Anvil - transmits vibrations from the malleus to the stirrup Hammer - help transmit vibrations from the eardrum to the inner ear ### **Unit 5: Electricity and magnetism (Chap 11-13)**