1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Biomechanics in space

  1. Mar 28, 2010 #1
    1. you and your partner are astronauts wearing 10kg space suits, you are drifting away from the space ship 0.1m/s and your partner is stationary directly between you and the space ship which is 100m away from your partner. The ship cannot move and no ones aboard to get you. You are fine but your partner is badly injured and unable to move! Oh and your holding a 20kg tool box.

    -->I need to get my injured partner and I to the space ship, I need to explain using conservation of linear and angular momentum how Im going to be able to do this...I was thinking pushing off the toolbox in a way? It would prevent me from going back 0.1m/s for sure and possibly get me to my partner, perhaps position myself in somersaulting postion?

    Not too sure!
     
  2. jcsd
  3. Mar 28, 2010 #2
    Oh man, now that's intense! Not sure if I would think of physics in a moment like this, but yeah, basically if you push off the 20Kg tool box in the direction where you are moving, you would change your velocity direction and now be drifted toward the spaceship. In the way back to the spaceship you would just collide with your partner (whom you would have to hold closely so to produce an 'inelastic collision') and finally make your way back to the spaceship (that last part with less velocity due to the change of mass).
     
  4. Mar 28, 2010 #3
    Should I turn my body into a certain position after take off? like head first perpendicular to my partner ahead? Also, near the end of the question it mentions that I need to have reasonable degree of control..so would I have to get me and my partner to spread out our arms and legs to increase moment of inertia...although I dont think that would make much of a difference in space..
     
  5. Mar 28, 2010 #4
    Oh, I don't think either that would make any difference, I mean it's not like there is any air friction. Therefore there is no need really to do anything, apart of holding your partner together so that the collision is inelastic and so on. Moreover your partner is injured, don't think he would agree to do some somersaulting lol.

    Anyway, I think that happened several times, sadly. I remember once, the news broadcast that such an incident occurred to an USSR astronaut. And nobody was able to rescue him, he just kept going to the same direction ad eternum... However nowadays I'm pretty sure they are not allowed to go outside without that kind of long-robotic-arm attached to the spaceship.
     
    Last edited: Mar 28, 2010
  6. Mar 28, 2010 #5
    Not only that, but Im pretty sure they need to have those rockets attached to their backs in order to maneuver in open space in the first place right?

    Also, which sort of equation would help me find out the answer to the question "once you catch your partner, calculate how long it will take you to get back to the space station if you can produce an impulse of 200 Newton seconds using a pushing action"
    ....So considering Im just head in a linear motion towards the shuttle would I just use L=mv...then once I find out the velocity get the 'seconds'?
     
  7. Mar 28, 2010 #6
    Yeah, as long as you know how many meters there are from your partner to the space shuttle, that should do it.
     
  8. Mar 28, 2010 #7
    Awesome, thanks Redsummers!
     
  9. Mar 28, 2010 #8
    You're welcome. And now you know, if you ever go to outer space, be sure to bring a tool box with you!
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook