Exam Review Flashcards
what is efficiency?
measures useful work done compared to the energy or work put into the machine
% efficiency= energy output-energy input X 100%
what is energy?
the ability to do work
what is work
the transfer or change or energy from one form to another
What is the first Right Hand Rule?
if the straight conductor is held in the right hand, the thumb points in the direction of the current and,the fingers curl in the direction of magnetic field lines
what is the second Right Hand Rule?
curl the fingers in the direction of the current, thumb points to the north pole.
what is the third Right Hand Rule?
Wrap your fingers around the wire in the direction of current flow through the wire. Your thumb represents the “North” direction of the induced magnetic field!
newtons 1st law
inertia, objects resist a change in motion. (object will continue at a stat of rest or at a constant speed in a straight line unless acted upon by an external force)
newtons 2nd law
if the external force is not zero, the object will accelerate in the direction of the net force. magnitude is directly proportional to the net force and slightly proportional to the mass.
newtons 3rd law
for every action force, there is a simultanious reaction force (boat question)
what is kinetics?
the study of objects that move
what is scalar
has magnitude only
what are vectors?
has magnitude and direction
how to convert from km/h to m/s
divide by 3.6
how do distance/ time graphs work?
when stationary, the line is flat, the stepper the line, the faster someone is moving.
true or false? if the force acting on an object on a frictionless surface is doubled, its acceleration will also double
true
true or false? all forces require objects to be in contact and cannot act at a distance
fasle
which force holds protons together in the nucleus of the atom?
strong nuclear forces
how are meters connected?
in series
what is an example of direct current?
something with a battery like a flashlight
what is an example of indirect current?
something plugged in like a fan or a fridge
true or false? when work is done energy is always lost in some sort of undesired form
true
true or false? power is the rate of doing work
true
true or false? if someones speed triples, their kinetic energy triples
fasle
when is work negative?
when the applied force is in the opposite direction of the displacement
how to convert kg to kN
1 kg = 101.7 kN
what is the law of conservation of energy?
energy can neither be created nor destroyed
what are standing waves?
waves dependent on frequency and the speed within the medium
what is the doppler effect?
the Doppler effect is the change in frequency or wavelength which causes a changed precieved sound for someone outside of the object
what are the laws of magnetic poles?
opposites attract, like repells, magnetic poles are strongest at the poles, north and south are equally strong, cut a megnet in twwo and recieve two smaller, weaker magnets,
what way do magnetic field lines move outside of a magnet?
from north to south all the time and thats the truth.
what is kirchoffs law for current
series - in a closed circuit, amount of current entering=amount leaving. I1=I2=I3…
parallel - I parallel= I1+I2+I3…
waht is kirchoffs law for voltage?
v series= v1+v2+v3
v parallel= v1=v2=v3…
how does the DC electric generator work?
theres a lot of coils with a soft iron core to make a strong magnetic field . its a split ring instead of a slip ring.
how do objects become charged?
friction, contact, and induction
what does the I symbol mean?
current, its measured in amps, A
what does the symbol Q mean?
charge, measured in coulombs, C
what does the symbol e mean?
elementary charge, measured in coulombs, C
what does the symbol N mean?
number.
what is energy measured in?
joules, J
what is resisance measured in?
ohms, the omega symbol
what is the law of conservation of energy?
ETi=ETf
ET= Eg+Ek
