A pion is an unstable particle that has an average lifetime of 2.55 x 10^ -8 s. This is the time interval?

Question

between its creation in a nuclear process and its extinction into decay products, as measured in a frame of reference at rest with respect to the pion. An average pion is traveling at 0.270c relative to earth. How far does it travel in its lifetime, relative to earth?

a) 3.22 m
b) 2.23 m
c) 2.15 m
d) 2.07 m

Answer 1

Answer is D

Speed of Particle = 3 x 10^8 x 0.270 = 8.1 x 10^7

Distance = Speed x Time
Distance = (8.1 x 10^7) x (2.55 x 10^-8)
Distance = 2.0655 metres or 2.07 metres (to 2 dp)

Answer 2

(2.55 x 10^ -8 s)(0.27)(300,000 km/s)(1,000 m/km) = 2.0655 m