Assuming a decay constant of 230 ns, how much time is required for a NaI(Tl) scintillation event to emit 99% of the total light yield

Aturntable a is built into a stage for use in a theatrical production. it is observed during a rehearsal that a trunk b starts to slide on the turntable 10 s after the turntable begins to rotate. knowing that the trunk undergoes a constant tangential acceleration of 0.31 m/s2, determine the coefficient of static friction between the trunk and the turntable.