<-- .. title: Laser Gun Recoil: Follow-up .. date: 2010-04-21 16:31:00 .. tags: recoil, laser, sound, momentum, gun .. category: old .. slug: laser-gun-recoil-follow-up .. author: Jesse --> Matt Springer over at [Built on Fact](http://scienceblogs.com/builtonfacts/)s has a [very nice post](http://scienceblogs.com/builtonfacts/2010/04/laser_rifle_recoil.php) following up on my earlier analysis of [whether or not a laser gun would recoil](http://thevirtuosi.blogspot.com/2010/04/today-id-like-to-approach-question-near.html). In my analysis I came to the conclusion that the momentum delivered was much less than that of a conventional gun, but that the impulse, and hence the force delivered, was about the same. However, that force was delivered over a \~30ns timescale, which left open the question of whether or not the wielder would be able to feel that recoil. While I had thought to possibly return to this issue at some point, Matt has beat me to it. This is fortuitous, because I wasn't sure quite where to start with the question, while he approaches it in a very sensible, clear manner. The gist of his post is that he compares our response to short time scale forces to our ability to sense sound. I won't go through his calculations, you can check those out for yourself, but he concludes that it is very unlikely that we could feel the recoil of our laser gun. Case closed. Though, like any good scientist, we may choose to reopen it later if more evidence comes to light.