Using lasers to decrease speed of sodium atoms

[BruceSpringste]

Hi!

Recently I have began to read up on my passion in physics in my spare time.
I have encountered an experiment where lasers are used to decrease the speed of sodium atoms. The lasers are a wavelength that the sodium atoms absorb and then proceed to emit a photon.

If the atoms are traveling at a speed of 1km/s and the laser decelerates the speed of the atoms by
10⁶m/s² how long will it take for them to completely come to a stop?

It is a simple question that I simply cannot get the right answer out of. I get the answer 1m but later in the text it mentions the stopping distance to approx. 0.5m!

What am I missing?

Thanks!

Edit: Just realized what I did wrong! Don't know how to delete posts!

 

[Valerie Park]

The answer is 0.1s. This can be calculated using the equation s = 1/2*a*t^2, where s is the distance traveled, a is the acceleration, and t is the time. In this case, s = 106m/s^2, a = -106m/s^2, and t = 0.1s.