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100 Cards in this Set
- Front
- Back
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SI units
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meter, kilogram, second
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M
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mega 10^6
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G
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giga 10^9
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k
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kilo 10^3
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c
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centi 10^-2
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m
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milli 10^-3
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base units
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L-length, M-mass, T-time
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significant figures
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subtracting/adding- least amount of decimal places
multiplying/dividing- least amount of significant figures |
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scientific notation
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In this notation a number is written as a product of a number between 1 and 10 and a power of 10.
ex. 3.4 x 10^3 = 3400 |
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scalar versus vector
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S- just magnitude. ex-temperature, mass, speed
V-magnitude and direction. ex-velocity, force, displacement, acceleration |
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adding vectors
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tail to tip method
parallelogram adding/subtracting |
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component method
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x and y directions
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axi+ayj=a
bxi+byk=b |
vector
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displacement
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xf-xi
distance from starting point, not caring about path vector |
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speed
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distance/time
scalar |
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velocity
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displacement/time
vector |
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instantaneous velocity
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limit of displacement/time
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acceleration
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velocity/time
vector instantaneous= the limit |
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negative acceleration
deceleration |
n- acceleration in the negative direction
d- acceleration opposite of velocity |
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speeding up versus slowing down
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speeding up- velocity and acceleration in same direction
slowing down- velocity and acceleration in diff. direction |
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linear kinetic equations
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x dimension
vf=vi+at Δx=vit+.5at^2 vf^2=vi^2+2aΔx y dimension vf=vi+at Δy=vit+.5gt^2 vf^2=vi^2+2gΔy |
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falling objects
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absense of air resistance in free fall, acceleration due to gravity
a=9.8m/s^2 |
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symmetry of tossing up an object
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Δt going up= Δt coming down
vC = vA , magnitude not direction v D up = v D down , magnitude not direction |
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freefall problems
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May need to divide the motion into segments
Possibilities include Upward and downward portions The symmetrical portion back to the release point and then the non-symmetrical portion |
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projectile motion
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in two dimensions
x and y |
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reference frame
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an extended object whose parts are at rest with respect to each other
ex- walking on a train |
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relative velocity
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in relationship with the reference frame
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V(ws)
V(bs) V(bw) |
v(bs)=V(bs)+V(bw)
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force
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vector
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contact/noncontact forces
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C= normal, friction, tension
nc= gravitational force, electrical force |
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Newton's First Law of Motion
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An object at rest remains at rest and an object moving with some velocity continues with that same velocity, unless something exerts an external force on it
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weight
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force of gravity = mass*gravity
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Newton's Second Law of Motion
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F=ma
When a net external force acts on an object of mass m, the resulting acceleration is directly proportional to the net force applied. The reciprocal of the mass is the constant of proportionality. The direction of the acceleration is the same as the direction of the net force. |
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normal force
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one component of the force that a surface exerts on an object with which it is in contact – namely, the component that is perpendicular to the surface.
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frictional force
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opposite and parallel to motion
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hooke's law
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F(restoring force)=-kx
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Tension Force
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When a cord (rope/string/wire) pulls on an object, it is said to be under tension and the force it exerts is tension
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Newton's Third Law of Motion
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Whenever one body exerts a force on a second body, the second body exerts an oppositely directed force of equal magnitude on the first body.
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Force notation
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First subscript- object that the force is being exerted on
Second subscript- source |
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free body diagrams
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identify all forces acting on an object
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static friction
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two surfaces not sliding against each other
keeps objects from sliding on inclines |
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Fs=usFn
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static friction equation
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kinetic friction
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opposes momentum
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Fk=ukFn
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kinetic friction equation
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Drag Force
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Force exerted on an object ,which is moving through a fluid (air or liquid)
opposes the motion of the object f=bv |
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terminal speed
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Speed at which the drag force balances the weight force and the acceleration of the falling object is zero
(mg/v)^1/n= Vt |
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center of mass
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m1v1+m2v2/(m1+m2)
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non uniform circular motion
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varying speeds in circular path
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Centripetal versus tangential direction
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C- towards center
T- towards velocity vector |
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tangential acceleration
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At=dv/dt
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centripetal acceleration
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Ac=v^2/r
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uniform circular motion
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same speed throughout, direction changes
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unbanked curve
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statis friction is the force
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banked curve
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v=sqrt(rgtan)
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work done by a constant force
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W=FΔxcos
joules |
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Total work
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W(total)=F1Δx1+F2Δx2
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centripetal motion does no work
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opposing direction of motion is negative
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energy
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ability to do work
K=.5mv^2 |
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Work is change in kinetic energy
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W=ΔK=.5mv^2-.5mv^2
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Work > 0
Work <0 |
K increases
K decreases |
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Scalar Dot Product
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A(dot)B=ABcos
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Work (dot product)
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W=F(dot)dl
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Power
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rate work is done
P=W/t=ΔK/t P=Fvcos |
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potential energy
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related to position
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Gravitation Potential Energy
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Ug=mgh
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GPE of system
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Ug=mgh(cm)
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Conservative versus Non Conservative Forces
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C- not dependent on path
ex.gravity, elastic force(spring) NC- dependent on path ex. friction, air resistence, tension |
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Potential Energy
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ΔU=Uf-Ui
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Hooke's Law
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F=-kx
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Spring Potential Energy
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U=.5kx^2
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Work Energy Theorem
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W(ext)=ΔE(mech)-W(nc)
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Conservation of Mechanical Energy
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E(mech)=K(sys)+U(sys)= constant
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conservation of energy
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W=ΔK=E(sys)=E(mech)+E(therm)+E(chem)+E(other)
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E(in)-E(out)= ΔE(sys)
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law of conservation of energy
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linear momentum
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P=mV
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Law of Conservation of Momentum
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When the sum of the external forces acting on a system of particles remains zero, the total momentum of the system remains constant
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center of mass reference frame
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u1=v1-vcm
u2=v2-vcm |
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Impulse
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I=FavΔt
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Types of collisions
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elastic- energy conserved
inelastic- energy not conserved perfectly inelastic- objects stick together |
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Elastic collision equations
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m1v1i+m2v2i=m1v1f+m2v2f
.5mv1i^2+.5mv2i^2=.5mv1f^2+.5mv2f^2 v1i-v2i=-(v1f-v2f) |
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perfectly inelastic collision equations
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m1v1i+m2v2i=Mvf
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collisions in two or more dimensions
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x and y components
vcos and vsin |
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Rotational Kinetic Equations
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wf=wi+@t
Δ0=wit+.5@t^2 wf^2=wi^2+2@Δ0 |
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angular velocity
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w=d0/dt
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angular acceleration
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@=wf-wi/t=Δw/t
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tangential angular velocity
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v(t)=rw
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tangential and centripetal angular accelerations
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A(t)=r@
A(c)=rw^2 |
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rotational kinetic energy
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K=.5Iw^2
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impulse in rotational motion
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I=mr^2
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torque
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torque=I@
torque=rF |
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rotational work and power
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dW=torque*d0
dP=torque*w |
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Rolling object
velocity and acceleration |
v(cm)=Rw
a(cm)=R@ |
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total kinetic energy of a rolling object
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K=.5Mv(cm)^2+.5I(cm)w^2
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right hand rule
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If fingers of right-hand curl in the direction of rotation, the thumb points in the direction of angular velocity
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Vector Cross Product
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AxB=ABsin
include i,j,k Torque=rxF |
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ij=k
jk=i ki=j ii=0 jj=0 kk=0 |
ji=-k
kj=-i ik=-j |
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angular momentum
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L=rxP
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spin and orbital angular momentum
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Lsys=Lorbit+Lspin
Lorbit=rcmxMvcm |
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Total angular momentum of the system
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L=Iw
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conservation of angular momentum (L)
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Lsys=constant
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