Question

An unstable elementary particle is known to decay

into other particles in 4 uus , as measured in a
laboratory where the particle are at rest. A beam of
'such particles is accelerated to a speed of 99.98
percent of the speed of light.
How long do the particles in the beam take to decay, in the laboratory frame of reference?

Answer 1

24.995 is most likely the answer

sorry if i'm wrong but yeah