Download Physics 201 Equations | PHYS 201 - Modern Physics and more Quizzes Physics in PDF only on Docsity! TERM 1 Ether Frame DEFINITION 1 the one frame through which light traveled at speed c in all directions; if the ether frame is assumed, then the earth must be moving rleative to it with the same velocity as its orbit around the sun: v=3*10^4 m/s TERM 2 Michelson-Morley Experiment DEFINITION 2 t_12l/c (1-^2 ) t_22l/c (1+1/2 ^2 ) tl/c ^2 TERM 3 Postulates of Relativity DEFINITION 3 1) if s is an inertial frame, and if a second frame s' moves with constant velocity relative to s, then s' is also an inertial frame 2) in all inertial frames, light moves with speed c in any direction TERM 4 Time Dilation DEFINITION 4 t^'=2h/c (in the frame s) t=t' (in the frame s) =(1-^2 )^(- 1/2) There is no difference unless the two frames are in relative motion The differences between the times gets bigger as v increases V must always be less than c tt' TERM 5 Proper Time DEFINITION 5 Time as measured in a reference frame in which the two events happen at the same place t=t_0 TERM 6 Half-Life DEFINITION 6 t_(1/2): average time for 1/2 initial no. of particles to have decayed t=nt_(1/2), there are N_0/2^n t_(lab)=time elapsed in lab frame=L/v t_(1/2) in lab frame = t_(1/2) in pion rest frame L_(pion rest frame)=L_(lab)/ TERM 7 Length Contraction DEFINITION 7 measured distance between two events depends on the frame relative to which it is measured lengths are measured differently in different rest frames lengths are only contracted in the direction of motion l=vt (rest frame s) l'=vt' (rest frame s') l=l'/ l=l_0/ where l_0=the length of an object measured in its rest frame(proper length) lengths perpendicular to the relative motion are unchanged TERM 8 Twin Paradox DEFINITION 8 L(rocket frame)=L(earth frame)/ T(rocket frame)=L(rocket frame)/v T(earth frame)=L(earth frame)/v T(rocket frame)=T(earth frame)/ TERM 9 Galilean Transformation DEFINITION 9 according to the ideas of classical physics: x'=x-vt y'=y z'=z t'=t **when v/c is small, the correct relation between these variables reduces down to the Galilean transformations** TERM 10 Lorentz Transformations DEFINITION 10 x'=(x-vt) y'=y z'=z t'=(t-(vx)/c^2) inverse transformations x=(x'+vt') y=y' z=z' t=(t'-(vx)/c^2)
