Physics Definitions Flashcards
The property of things to resist changes in motion
Inertia
Every object continues in a state of rest, or of uniform speed in a straight line, unless acted on by a nonzero net force
Newtons first law of motion (law of inertia)
In the simplest sense, a push or a pull
Force
The vector sum of forces that act on an object
Net force
An arrow drawn to scale, used to represent a vector quantity
Vector
A quantity that has both magnitude and direction, such as force
Vector quantity
A quantity that has magnitude but not direction, such as mass and volume
Scalar quantity
The net result of a combination of two or more factors
Resultant
The state of an object or system of objects, for which there are no changes in motion. An accord with newtons first law, if an object is at rest, the object stays at rest. If an object is moving, it’s motion continues without change.
Mechanical equilibrium
For any object or system of objects and equilibrium, the sum of the forces acting equals zero
Equilibrium rule
How fast an object moves ; the distance traveled per unit of time
Speed
The speed at any instant
Instantaneous speed
The total distance traveled divided by the time of travel
Average speed
An object’s speed and direction of motion
Velocity
A quantity that has both magnitude and direction
Vector quantity
A quantity that has only a magnitude, not a direction
Scalar quantity
The rate at which velocity changes with time ; the change in which velocity may be in magnitude, or direction, or both
Acceleration
Motion under the influence of gravity only
Freefall
Any push or pull exerted on an object, measured in newtons
Force
The resistive force that opposes the motion or attempted motion of an object either passed another object with which it is in contact or through a fluid
Friction
The quantity of matter in an object. More specifically, it is the measure of the inertia or sluggishness that an object exhibit in response to an effort made to start it, stop it, deflect it, or change in anyway it’s state of motion.
Mass
The force upon an object due to gravity (mg)
Weight
The fundamental SI unit of mass. 1 kg is the mass of 1 L of water at 4°C.
Kilogram
The SI unit for force. 1 N is the force that will give an object of mass 1 kg in acceleration of 1 m/s^2
Newton
The quality of space an object occupies
Volume
The acceleration of an object is directly proportional to the net force acting on the object, is in the direction of the net force, and is inversely proportional to the mass of the object.
Newton second law
The speed at which the acceleration of a falling object terminates, because a resistance balances gravitational force
Terminal speed
Terminal speed with direction specified
Terminal velocity
Whenever one object exerts a force on a second object, the second object exerts an equal and opposite force on the first
Newtons third law
Mutually perpendicular vectors, usually horizontal and vertical, whose vector sum is a given vector
Components
The product of the mass of an object and its velocity
Momentum
The product of the force acting on an object and the time during which it acts
Impulse
Impulse is equal to the change, in the momentum of the object that the impulse acts upon
Impulse momentum relationship
In the absence of an external force, the momentum of a system remains unchanged. Hence, the momentum before an event involving only internal forces is equal to the momentum after the event.
Law of conservation of momentum
A collision in which objects rebound without lasting deformation or the generation of heat
Elastic collision
A collision in which objects become distorted, generate heat, and possibly stick together
Inelastic collision
The product of the force and the distance moved by the force
Work
The time rate of work ; rate at which energy is expended
Power
The property of a system that enables it to do work
Energy
Energy to to the position of something or the movement of something
Mechanical energy
Energy that something possesses because of its position
Potential energy
Energy that something possesses because of its motion, quantified by the relationship
Kinetic energy
The work done on an object equals the change in the kinetic energy of the object
Work energy theorem
Energy cannot be created or destroyed ; it may be transformed from one form into another, but the total amount of energy never changes
Law of conservation of energy
A device, such as a lever or pulley, that increases or decreases a force, or simply changes the direction of a force
Machine
The work output of any machine cannot exceed the work input. An ideal machine, where no energy is transformed into thermal energy ; (work input = work output)
Conservation of energy
A simple machine consisting of a rigid rod pivoted at a fixed point called the fulcrum
Lever
The percentage of the work put into a machine that is converted into useful work output
Efficiency
The linear speed tangent to a curved path, such as in circular motion
Tangential speed
The number of rotations or revolutions per unit of time ; often measured in rotations or revolutions per second or per minute
Rotational speed
The property of an object to resist any change in its state of rotation : if rest the body tends to remain at rest ; if rotating, it tends to remain rotating and will continue to do so unless acted upon by an external net torque
Rotational inertia
The product of force and lever-arm distance, which tends to produce or change rotation
Torque
The average position of the mass of an object.
Center of mass
The average position of wait for the single point associated with an object where the force of gravity can be considered to act
Center of gravity
The state of an object in which it is not acted upon by a net force or a net torque
Equilibrium
A force directed toward a fixed point, usually the cause of circular motion
Centripetal force
And upward force a parent in a rotating frame of reference. It is a parent in the sense that is not part of an interaction, but is a result of rotation, with no reaction force counterpart.
Centrifugal force
The product of the mass of an object and it’s linear velocity
Linear momentum
The product of a bodies rotational inertia in rotational velocity about a particular access. For an object that is small compared with the radio distance, angular momentum can be expressed as the product of mass, speed, and radio distance of rotation.
Angular momentum
When no external torque acts on an object, or a system of objects, no change of angular momentum can occur. Hence, the angular momentum before an event involving only internal torques or no torques is equal to the angular momentum after the event.
Conservation of angular momentum
Every body in the universe attracts every other body with a force that, for 2 bodies, is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centers
Law of universal gravitation
A law that relates the intensity of an effect to the inverse square of the distance from the cause. Gravity follows an inverse square law, as do the effects of electric, magnetic, light, sound, and radiation phenomena.
Inverse square law
The force that an object exerts on a supporting surface, which is often, but not always, due to the force of gravity
Weight
Being without a supported for us, as in freefall
Weightless
High or low tides that occur when the sun, earth, and the moon are all lined up so that the tides due to the sun in the moon coincide, make the high tides higher than average in the low tides lower than average
Spring tides
Tides that occur when the moon is midway between noon, and four, and either direction. Tides due to the sun in the moon partly cancel, making the high tide slower than average in the low tides higher than average.
Neap tides
The influence that a massive body extends into the space around itself, producing a force on another massive body. It is measured in newtons per kilogram.
Gravitational field
A concentration of mass that results from gravitational collapse, near which gravity is so intense that not even light can escape
Black hole
Any object that moves through the air or through space under the influence of gravity
Projectile
The curved path followed by a projectile under the influence of only constant gravity
Parabola
A projectile or small celestial body that orbits a larger celestial body
Satellite
The oval shaped path followed by a satellite. The sum of the distances from any point on the path to two points called foci is a constant. When the foci are together at one point, the ellipse is a circle. As the foci get farther apart, the eclipse becomes more eccentric.
Ellipse
The path of each planet around the sun is an ellipse with the sun at one focus
Kepler’s law 1
The line from the sun to any planet sweeps out equal areas of space an equal time intervals
Kepler’s law 2
The square of the orbital period of a planet is directly proportional to the cube of the average distance of the planet from the sun
Kepler’s law 3
The speed that a projectile, space probe, or similar object, must reach to escape the gravitational influence of earth or of another celestial body to which it is attracted
Escape speed
The smallest particle of an element that has all of the elements chemical properties
Atom
The haphazard movement of tiny particles suspended, and a gas or liquid that results from their bombardment by the fast moving atoms or molecules of the gas or liquid
Brownian motion
The number that designate the identity of an element, which is the number of protons in the nucleus of an atom
Atomic number
An electrically charged atom ; an atom with an excess or deficiency of electrons
Ion
Atoms with the same element that contain different numbers of neutrons
Isotopes
The standard unit of atomic mass, which is equal to 1/12 the mass of the most common atom of carbon
Atomic mass unit
A material in which atoms of different elements are chemically bonded to one another
Compound
A substance who’s components are mixed together without combine chemically
Mixture
Two or more atoms that bond together by a sharing of electrons
Molecule
A complementary form of matter, composed of atoms that have negative nuclei and positive electrons
Antimatter
Unseen and unidentified matter that is evidence by its gravitational pull on stars in the galaxies.
Dark matter
The linking together of atoms to form, larger structures, including solids
Atomic bonding
A mass of a substance per unit volume
Density
The property of immaterial by which it changes shape when a deforming force acts on it and returns to its original shape when the forces removed
Elasticity
The amount of stretch or a compression of an elastic material is directly proportional to the applied force
Hookes law
The study of how size affects the relationships among weight, strength, and surface area
Scaling
The ratio of forced to an area over which that force is distributed
Pressure
The upward force that a fluid exerts on and immersed object
Buoyant force
An immersed body is buoyed up by a force, equal to the weight of the fluid it displaces
Archimedes principle
A floating object displaces, a weight of fluid equal to its own weight
Principle of flotation
The pressure applied to emotionless fluid can find in a container is transmitted undiminished throughout the fluid
Pascals principle
The tendency of the surface of a liquid to contract in an area in those behave like a stretched elastic membrane
Surface tension
The rise of a liquid in a fine hollow tube or in a narrow space
Capillarity
The pressure exerted against bodies immersed in the atmosphere. Results from the weight of air pressing down from above.
Atmospheric pressure
A device that measures atmospheric pressure
Barometer
The product of pressure and volume is a constant for a given mass of confined gas as long as the temperature remains unchanged
Boyles law
An object in the air is buoyed up with a force equal to the weight of the displaced air
Archimedes principle for air
Where are the speed of a fluid increases, the internal pressure in the fluid decreases
Bernoulli’s principle
An electrified gas that contains ions and free electrons. Most of the matter in the universe is in the plasma phase.
Plasma
A measure of the average translational kinetic energy per molecule, any substance, measured in degrees Celsius, or Fahrenheit or in kelvins
Temperature
The lowest possible temperature that a substance may have — the temperature at which molecules of the substance have their minimum kinetic energy
Absolute zero
The energy that flows from a substance of higher temperature to a substance of lower temperature, commonly measured in calories or joules
Heat
The total of all molecular energies, kinetic plus potential, that our internal to a substance
Internal energy
The quantity of heat per unit mass required to raise the temperature of a substance by 1 Celsius degree
Specific heat capacity