Physics Units and Vectors Flashcards
length
mass
time
current
amt
temperature
luminous intensity
force
work and energy
power
length - meter - m
mass - kg
time - s
current - ampere (C/S) = A
amt = mole - mol
temperature - kelvin - K
luminous intensity - candella - cd
force - newton (kgm/s^2)
work and energy - Joule (kgm^2/s^2)
power - erg per second or watt (kg*m^2/s^3)
what is an angstrom and a nanometer?
what is energy on atomic scale in electron volts?
angstrom = 1 A = 10^-10 m
nanometer = 1 nm = 10^-9 nm
electron volts (1 eV = 1.6 *10^-19 J)
which is amount of E gained by an e accelerating through a potential difference of one volt
vector vs scalar
examples of vector vs scalar
displacement vs distance
vectors have mag and direction
scalars have only mag
scalar = distance, speed, energy, pressure, mass
vectors = displacement, velocity, acc, force
Distance is the length of the path taken by an object whereas displacement is the simply the distance between where the object started and where it ended up
splitting vectors in components in x and y direction
cos theta = X/V
sin theta = Y/V
what is the resultant of a x and y vector length?
use pythagorean theorem
how do we sum vectors to make a big vector?
how do we subtract vectors?
still tip to tip
like vector addition but it points down if we subtract
(points up if we add)
what happens when we multiply a vector by a scalar
mag changes
direction does not
what is the dot product?
when we multiply 2 vectors and want to make a scalar like work
what is the cross product?
when we multiply 2 vectors and want to make a third vector like torque
we need mag and direction
resultant of cross product is always perpindicular to plane of two vectors
we use the right hand rule for the direction of the vector
what is the right hand rule?
used to determine direction of vector
vector multiplication is not commutative. Explain
3 x 4 = 4 x 3
vector A * Vector B not equal to vector B * Vector A
