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!

Conservation of momentum problem regarding a missing mass of a ship!

  1. Mar 5, 2013 #1
    1. The problem statement, all variables and given/known data

    After a malfunction, an astronaut escapes from a doomed spacecraft by using an escape pod that is blown off of the ship. The small explosion sends the pod flying away at 34.9 m/s, while the main ship moves in the opposite direction at the speed of 1.89 cm/s. If the combined mass of the astronaut and pod is 1270 kg, what is the mass of the doomed spacecraft?

    2. Relevant equations

    Conservation of Momentum:

    m1u1+m2u2 (initial) = m1v1+m2v2 (final)



    3. The attempt at a solution

    I believe that conservation of momentum is the correct principle to use here, but I am unsure how to solve for the spaceship's mass because of the missing initial velocity. Could someone help me out? Thanks!
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. Mar 5, 2013 #2

    Bandersnatch

    User Avatar
    Science Advisor
    Gold Member

    Hi there!

    The initial velocity was meant to be 0 for both the ship and the pod.
    Those velocities provided are for after the separation, relative to their mutual centre of mass.
     
  4. Mar 5, 2013 #3
    If the spaceship and pod before the launch had 0 momentum to their mutual centre of mass, the conservation of momentum says:

    the pod and spaceship must have right after the launch 0 momentum to their mutual centre of mass. So you have 4 variables ( as intial velocities were both 0 ) after the launch; ( mass and velocity of spaceship and pod ).
     
  5. Mar 5, 2013 #4
    thank you! i figured that the velocity must have been an unknown constant (which would be ridiculous) or 0. I just wanted verification. Thank you for the fast reply guys!
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Similar Discussions: Conservation of momentum problem regarding a missing mass of a ship!
Loading...