A subatomic particle created in the upper atmosphere travels at 6 x 107 meters per second.It travels a distance of 3x10–4 meters before it radioactively decays.

Question

How much time does the subatomic particle take to cover this distance?

Answer 1

distance = rate x time, so time = distance/rate

d/r = (3 x 10^-4)/(6 x 10⁷) 3/6 = 0.5; also 10^-4/10⁷ = 10^{-4 - 7} = 10^-11

0.5 x 10^-11 or 5 x 10^-12 seconds

Answer 2

speed:

6E7m=1second

distance:

3E-4 m

time=? seconds

start with distance, use time as a conversion:

(3E-4 m) (1 second / 6E7m)=5E-12 seconds

5×10^-12 seconds