Calculating Particle Speed with Relativity

[GingerToast21]

Find the speed of a particle that takes 2.0 y longer than light to travel a distance of 6.7 ly. Answer is wanted in terms of 'c'.



delta(t)= delta(t0)/(sqrt(1-(v/c)^2)).



8.7= 1/(sqrt(1-(v/c)^2))-->
1/8.7=sqrt(1-(v/c)^2-->[/b]
(1/8.7)^2=1-(v/c)^2-->[/b]
(v/c)^2=1-(1/8.7)^2-->[/b]
v/c=sqrt(1-(1/8.7)^2)-->[/b]
v/c=0.993372-->
v=0.993372c...which is incorrect, any assistance would be greatly appreciated[/b]
note: I also tried delta(t) to be 4.7...also incorrect

 

[dx]

What is the speed of light in units of light-years per year? It's just one! Light travels one light-year per year.

The particle travels 6.7 light-years in (6.7 + 2) years, so it's speed in units of light-years per year is ... ?

 

[GingerToast21]

What is the speed of light in units of light-years per year? It's just one! Light travels one light-year per year.

The particle travels 6.7 light-years in (6.7 + 2) years, so it's speed in units of light-years per year is ... ?

Thank you so much! That makes perfect sense. I hate when I over-complicate problems like these. Much appreciated!