The mean lifetime of stationary muons is measured to be 2.2000 μs. the mean lifetime of high-speed muons in a burst of cosmic rays observed from earth is measured to be 15.870 μs. to five significant figures, what is the speed parameter β of these cosmic-ray muons relative to earth?

What even is this. where is the question

Aform of energy that is reflected or emitted from objects in the form of electrical and magnetic waves that can travel through space. there are many forms of  electromagnetic  energy including gamma rays, x rays, ultraviolet radiation, visible light, infrared radiation, microwaves and radio waves.