Adisc rotates at a constant angular speed. the turn around time (t) is 0.5 seconds.
a point x of the disc is located at a distance of 20 cm from the center.
a: calculate the speed of the disc
b: calculate the web speed of x
c: calculate the angular speed of the disc
d: calculate the midpoint angle over which the disc rotates in 4 seconds.
e: calculate the path that the point x travels in 4 seconds.
can someone solve this

Space-time metric ds2= -dt2+at2dx2+bt2dy2+ct2dz2 (a)how does the area of a rectangle with vertices at ( x=0, y=0, z=0 ), (1,0,0 ), ( 0,1,0 ) and (1,1,0 ) changes with time? (b) if a photon moving in the x direction starts from the origin at t=1, when does it reach x=l? (ds=0 for the trajectory of a photon.) (c) the proper time for a particle is defined by cd=ds. what is the proper time for a particle to move along the trajectory ( x(t)=t, y(t)=0, z(t)=0 ) from t=0 to 1 ? what is the condition on the parameter a so that the velocity of the particle never exceeds the speed of light ?

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