Calculating Average Lifetime of Particles at Rest

[msimard8]

Heres the question before I say anything else

A beam of unknown elementary particles travels at a speed of 2.0 x 10^6 m/s. Their average lifetime in th ebeam is measrured to be 1.6 x 10^-8 s. Caclulate their average lifetime when at rest.

hmm I have no examples to go by. I figure I will have to use the formula

tm = ts/[sqrt(1-v^2/c^2)]

where tm is the time it takes when the object is moving (for example when viewing from Earth and ts is the stationary time, v is speed of the object and c is speed of light)

I tried to do this by plugging in the numbers as

ts=?
v=2.0x10^8 m/s
tm=1.6x10^-8

I didn't get the right answer of 1.2 x 10^-8 s so I am assuming I am wrong.
How do I do this correctly.

 

[Kurdt]

Well you are using the right formula and I get the right answer when I plug the numbers in. If you tell us what answer you get perhaps we can tell you what you're doing wrong.

EDIT: just noticed you cited

I tried to do this by plugging in the numbers as

ts=?
v=2.0x10^8 m/s

as what you've input.

That could be the problem.