# Physics terms

## 91 terms · In a few moments you're going to be feeling a little PRESSURE. Wait, that's chem..... -Jordan D. Thompson misquoting Brian Regan

### Acceleration

the amount an object's velocity has changed divided by the time period over which that change took place; a vector quantity

### Acceleration due to gravity on Earth

the time rate of change in velocity for an object that falls down toward the Earth, if resistance is considered to be negligible; the value near the surface of the earth is 9.80 m/s2

### Amplitude

in a wave or a sine curve that represents simple harmonic motion, the distance from equilibrium to the peak (or from equilibrium to the trough)

### Angular momentum

a value that measures how much spinning inertia (or mass in motion) an object has; can be thought of as a measure of how hard it would be to stop an object from spinning around a central axis

### Angular velocity

a value that measures how fast an object is either rotating or moving around a central axis

### Battery

a device that will supply energy to a circuit by establishing a potential difference

### Capacitance

the ability an object has to hold charge when it is subjected to a potential difference

### Capacitor

a device that is designed to store energy in the form of an electric field by holding charge

### Centripetal acceleration

an acceleration toward the center of an object that is moving circularly around a central point; comes from the Greek word that means "center seeking"; this vector is directed toward the center of the circular path

### Conductors

materials through which electrons can move somewhat freely

### Conservation of energy

refers to the fact that a closed system with only conservative forces acting on it will never change its total energy value

### Conservative force

a force that merely transfers energy between different internal energy systems for an object; will not add energy or take energy away from an object

### Constructive interference

the addition of two wave amplitudes that results in an overall greater displacement for the resulting wave

### Converging lens

a lens that will attempt to focus
light rays to a specific point due to its geometry

### Coordinate system

a measuring system where an origin is defined and the directions of positive and negative are chosen; a perpendicular system is often chosen

### Coulomb's law

the mathematical relationship that measures how much force will be felt between two charged objects at a certain distance from one another

### Destructive interference

the addition of two wave amplitudes that results in less net displacement

### Displacement

the change in position of an object regardless of the path taken to make the change; a vector quantity

### Distance

the magnitude of displacement that takes into account the path taken to make the change; a scalar quantity

### Diverging lens

a lens that, due to its geometry, will defocus light rays as if they came from a specific point

### Elastic collision

a collision in which both momentum and kinetic energy are conserved

### Electric charge

an inherent measure of an object caused by the imbalance of positive and negative charges on the object

### Electric current

the amount of electric charge that passes by a point in a certain time period

### Electric field

a construct used to quantify how much electric force a test charge would feel when placed next to a source charge; a vector quantity

### Electric potential

potential energy associated with an electric field divided by the charge in that field; commonly referred to as voltage; batteries are measured in terms of electric potential; a scalar term

### Electrical potential energy

the energy associated with the force between closely situated electric charges

### Electric power

the measurement of how much electric energy a circuit element is using in a given time period

### Electromotive force (EMF)

an archaic term for the potential difference value for a battery

### Energy

an internal quantity that is stored in an object that may be used for motion or work or may be transferred to another object; a scalar quantity

### Equivalent resistance

the resistance found when a circuit is broken down by combining circuit elements to create a new equivalent circuit

### Estimation

an educated guess or calculation of a value that is usually performed quickly so that you get a general idea of the range of that value

### Force

an interaction between two objects that may or may not affect the subsequent motion of either object; Newton's laws of motion detail how this affects the motion of an object; a vector quantity

### Force diagram

a diagram used to visually keep track of all the forces acting on an object; all forces should be written with reasonable approximations of their magnitudes and directions

### Force of gravity

the force of attraction between two objects that have mass; keeps you from floating off of the Earth

### Frequency

in a wave or a sine curve that represents simple harmonic motion, it's the number of complete wave oscillations the wave makes in a second; the inverse of period

### Friction

a resistive force that arises when two objects rub against each other

### Hypothesis

an idea, usually based upon earlier experiments or an observation of a physical phenomenon; an important step in the scientific method

### Impulse

the amount of force that is imparted by an object over a time period while it is trying to change the momentum of another object; it's the change in momentum and is a vector quantity

### Incident light ray

an initial light ray that is moving through one medium and then encounters another medium

### Index of refraction

a ratio that measures how much slower light travels in a given medium compared to the speed of light in a vacuum

### Induction

the process by which you rearrange the electrons present in a material in order to attract it to a charged object

### Inelastic collision

a collision in which momentum is conserved but kinetic energy is not conserved

### Insulators

materials in which electrons will feel a significant resistance when they attempt to move through

### International System of Units (SI)

a system of units that utilizes meters, kilograms, and seconds as its base units for length, mass, and time (respectively)

### Junction rule

the Kirchhoff rule that states that the sum of the currents entering any junction must equal the sum of the currents leaving that junction; it is a statement of conservation of charge

### Kinematics

the study of the motion of objects

### Kinetic energy

a form of energy that quantitatively measures how much motion an object has

### Kinetic friction

a force between two objects in contact with one another as one object is moving over the other; the force resists the motion and attempts to slow down the moving object

### Light rays

rays that emanate from an object and move in a straight line away from the object

### Longitudinal wave

a wave in which the displacement of the medium is in the same direction as the motion of the traveling wave

### Loop Rule

the Kirchhoff rule that states that the sum of the voltage differences across all the elements around any closed circuit must be zero; it is a statement of conservation of energy

### Magnetic fields

a construct used to quantify how much magnetic force a current can exert on a separate moving charge

### Magnetic flux

the amount of magnetic field lines that pass through a given area

### Mechanics

the study of what causes the motion of an object to occur

### Medium

a substance that has a tendency to return to equilibrium when displaced; a traveling wave will propagate through this

### Moment of inertia

quantitatively measures how much effort it will take to change an object's angular motion

### Momentum

the amount of motion an object has that is represented by the multiplication of the object's mass times its velocity; a vector quantity

### Non-conservative force

a force that changes the total energy of an object when it acts over a distance and thus performs work on it

### Normal force

the contact force that arises when two objects are contacting each other; the direction of this force vector will be perpendicular to the contact surface

### Ohm's law

the relationship between potential difference, electric current, and resistance for a given circuit element; does not apply for all materials

### Path length difference

the difference in length between the paths of two waves that will result in wave interference

### Peak

the highest point that a wave is displaced from equilibrium

### Period

in a wave or a sine curve that represents simple harmonic motion, the time that it takes for the motion to repeat

### Permeability of free space

a universal constant that is used in magnetic force calculations; represented by the symbol μo

### Permittivity of free space

a universal constant that is used in electrical force calculations; represented by the symbol εo

### Phase

the state of the displacement of a wave at a particular time; if it changes, then its displacement will automatically change

### Position

how far and in what direction an object is from the origin in a coordinate system; a vector quantity

### Potential energy

a form of energy that is stored for later use; may either be transferred to another energy form, such as kinetic energy, or transferred to another object in the form of work

### Projectile

an object that has motion in both the vertical and horizontal directions and falls solely under the influence of gravity while in the air

### Reflected light ray

the light ray that results when an incident light encounters another medium and bounces back into its original medium

### Refraction

the bending of a light ray that will occur as an incident light ray moves into a different medium

### Resistance

the ability of a material to slow the conduction of electrons through it

### Right Hand Rule 1 (RHR1)

the rule that allows you to find the direction of the magnetic field that emanates from a current; if you put your thumb in the direction of current flow while grasping the wire, then your fingers will curl in the direction of the resulting magnetic field

### Right Hand Rule 2 (RHR2)

the rule that allows you to find the direction of the force that results from a charge moving in a magnetic field; if you put your thumb in the direction of the velocity of the positive moving charge, and your forefinger in the direction of the external magnetic field, then the resulting middle finger will point in the direction of the magnetic force

### Scalars

quantities that only need a numerical value to fully describe them

### Scientific method

a method used to advance humankind's knowledge by analyzing facts and data in order to find out more about the universe

### Simple harmonic motion (SHM)

periodic motion that arises from a restoring force acting on a system; the resulting motion will oscillate on either side of an equilibrium value and resemble a sinusoidal curve

### Speed

the magnitude of velocity; a scalar quantity

### Static friction

a force between two objects in contact with one another that attempts to keep the two objects in stationary contact by resisting the attempted motion of one of the objects

### Superposition

the resulting addition of two waves interacting at the same place at the same time

### Torque

the quantitative measure of how much effective force is being exerted in trying to rotate something around an axis; a vector quantity

### Transverse wave

a wave in which the displacement of the medium is perpendicular to the direction of motion of the wave

### Traveling wave

a wave that propagates through some type of matter thereby transferring energy and momentum from one spatial location to another

### Trough

the lowest point a wave is displaced from equilibrium

### Vectors

quantities that need both a numerical value and a direction to fully describe them

### Velocity

the displacement of an object divided by the time period over which it took place; a vector quantity

### Wave interference

the result when two or more waves get together at the same location and at the same time