objects
frequency —the number of cycles per second of periodic motion; also, the number of wavelengths of a
wave passing a certain point per second
friction —a force acting parallel to two surfaces in contact; if an object moves, the friction force always
acts opposite the direction of motion
fulcrum —the point about which an object rotates g —free-fall acceleration near the Earth’s surface,
about 10 m/s^2
induced EMF —the potential difference created by a changing magnetic flux that causes a current to flow
in a wire; EMF stands for “electro-motive force,” but the units of EMF are volts .
inductance —the property of an inductor that describes how good it is at resisting changes in current in a
circuit
inductor —a coil in a circuit that makes use of induced EMF to resist changes in current in the circuit
inelastic collision —a collision in which kinetic energy is not conserved, as opposed to an elastic
collision, in which the total kinetic energy of all objects is the same before and after the collision
inertia —the tendency for a massive object to resist a change in its velocity
internal energy —the sum of the kinetic energies of each molecule of a substance
ion —an electrically charged atom or molecule
kinetic energy —energy of motion
Kirchoff’s laws —in a circuit, 1) at any junction, the current entering equals the current leaving; 2) the
sum of the voltages around a closed loop is zero
Lenz’s law —the direction of the current induced by a changing magnetic flux creates a magnetic field
that opposes the change in flux
magnetic field —a property of a region of space that causes magnets and moving charges to experience a
force
magnetic flux —the amount of magnetic field that penetrates an area
magnitude —how much of a quantity is present; see “scalar” and “vector”
mass spectrometer —a device used to determine the mass of a particle
rotational inertia —the rotational equivalent of mass
momentum —the amount of “oomph” an object has in a collision, equal to an object’s mass multiplied by
that object’s velocity
net force —the vector sum of all the forces acting on an object
normal force —a force that acts perpendicular to the surface on which an object rests
nucleus —the small, dense core of an atom, made of protons and neutrons
oscillation —motion of an object that regularly repeats itself over the same path
parallel —the arrangement of elements in a circuit so that the charge that flows through one element does
not flow through the others
perfectly inelastic collision —a collision in which the colliding objects stick together after impact
period —the time it takes for an object to pass through one cycle of periodic motion; also, the time for a
wave to propagate by a distance of one wavelength
potential energy —energy of position
power —the amount of work done divided by the time it took to do that work; also, in a circuit, equal to
the product of the current flowing through a resistor and the voltage drop across that resistor
resistance —a property of a circuit that resists the flow of current
resistor —something put in a circuit to increase its resistance