Conservation of momentum problem regarding a missing mass of a ship

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Homework Help Overview

The problem involves the conservation of momentum in a scenario where an astronaut escapes from a malfunctioning spacecraft using an escape pod. The velocities of both the pod and the main ship after the explosion are provided, along with the combined mass of the astronaut and pod. The challenge lies in determining the mass of the spacecraft given the missing initial velocity.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • Participants discuss the application of conservation of momentum and question the initial conditions, specifically the initial velocities of the ship and pod. There is a focus on understanding how these conditions affect the momentum calculations.

Discussion Status

Some participants have provided clarifications regarding the initial velocities, suggesting they were intended to be zero. This has led to further exploration of how the conservation of momentum applies to the situation, with acknowledgment of the variables involved post-launch.

Contextual Notes

There is a noted uncertainty regarding the initial velocities of the spacecraft and pod, which are critical for applying the conservation of momentum principle effectively. Participants are verifying assumptions about these initial conditions.

MichaelDunlevy
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Homework Statement



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 ?

Homework Equations



Conservation of Momentum:

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



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!
 
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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.
 
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 ).
 
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!
 

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