Semester 2 Exam Review Flashcards
Gravitational potential energy depends on
mass and height
kinetic energy depends on
mass and velocity
mechanical energy
the sum of kinetic energy and all forms of potential energy
law of conservation of energy
in a closed, isolated system, energy cannot be created nor destroyed, only transformed
Work-Energy Theorem
work is equal to the change in kinetic energy
impulse
force times change in time; change in momentum
conservation of momentum
when the system is closed and isolated (no masses or forces coming or leaving the system)
perfectly inelastic (what happens and what is conserved?)
objects stick together after collision; momentum is conserved
inelastic (what happens and what is conserved?)
objects deform during collision; momentum is conserved
elastic (what happens and what is conserved?)
objects bounce, move separately after collision; momentum and kinetic energy are conserved
impulse-momentum theorem
the impulse on an object is equal to the object’s final momentum minus the object’s initial momentum
conducter
charges (electrons) are free to move
insolator
charges (electrons) are bound
charging by contact (friction)
when there is friction between two unlike materials, the one with the greater electron affinity will gain electrons from the other material; insulators
charging by conduction
when a charges object touches a neutral conductor, electrons mover in or out, and the conductor becomes positive or negative; conductor
polarization
when a charged object comes close to a neutral object, electrons shift positions; one end becomes negative, and the other end positive, but overall the object is still neutral; both insulators and conductors
charging by induction
1)neutral object is polarized; 2) neutral object is connected to ground, and electrons move into or out of the ground; 3)original charged rod is removed, remaining electrons spread out; conductors
coulomb’s law
the magnitude of the force between charge A and charge B, separated by a distance R, is proportional to the magnitude of the charges and inversely proportional of the distance between them; F= (AB)/(R^2)
direction in an electron field
defined by the direction a small, positive test charge would go in that field
electrical potential difference (definition)
work done moving a small, positive test charge between two points in an electric field divided by the magnitude of the test chage
electric potential difference (synonym)
voltage
electric potential energy (synonym)
work
volts
joules/coulomb
current
flow of electric charge
amps
coulombs/second
what causes current?
an electrical potential difference (voltage) causes charges to flow from a position with high potential energy to a position with low potential energy
resistance depends on
length, diameter, temperature, and material
resistor
controls current in a circuit (keeps it from getting too high)
short circuit
when resistance is very low in a circuit, causing current to be high
what happens in a short circuit?
circuit elements get very hot
Ohm’s Law
current in a circuit has a direct relationship with voltage and an inverse relationship with resistance
adding a resistor to a series causes resistance to… and current to…
increase, decrease
adding a resistor to a parallel causes resistance to… and current to…
decrease increase
source of direct current
battery
source of alternating current
household outlets
fuse
stops current because it melts and opens the circuit
circuit breaker
stop circuit because a bimetallic strip bends open to open the circuit
GFI
a safety device tat checks for differences between current going into an appliance and current coming out of an appliance
domain
a group of electrons whose individual magnetic field are aligned
domains in a magnet
permanently aligned in a permanent magnet; temporarily aligned in a temporary magnet
electric motor
converts electrical energy into mechanical energy
electric generator
converts mechanical energy into electrical energy
increase strength of an electromagnet (3)
1) increase the number of coils 2)insert a ferromagnetic (i.e. iron) rod 3)increase current in the wire
simple harmonic motion
WE NEED THIS
wave
a disturbance that travels through space and time
wave speed depends on…
MATERIAL ONLY
amplitude of a wave depends on…
the source
frequency/period of a wave depends on…
the source
wavelength depends on…
speed and frequency
transverse wave
particles vibrate perpendicular to the direction of wave motion
longitudinal wave
particles vibrate parallel to the direction of wave motion
resonance
small forces are added to a vibrating system at a frequency that matches the natural frequency of the system
pitch
frequency of a sound
volume
amplitude of a sound
