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Final velocity, incomplete equation (answear included)

  • #1

Homework Statement



A space vehicle travelling at a velocity of 1200ms -1 separates by a controlled explosion into two sections of mass 865kg and 2010 kg. The two parts carry on in the same direction with the heavier rear section moving 120 ms -1 slower than the lighter front section. Determine the final velocity of each section.

Homework Equations





The Attempt at a Solution


i got as far as this on the equation however im stuck
(865+2010)*1200=865*V+(V-120)*2010=2875*…

we have been told that V=1284m/s
and heavier body velocity=1164m/s
 

Answers and Replies

  • #2
gneill
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i got as far as this on the equation however im stuck
(865+2010)*1200=865*V+(V-120)*2010=2875*…

we have been told that V=1284m/s
and heavier body velocity=1164m/s
Well, you're almost there. You've got an equation that can be solved for V:

(865+2010)*1200=865*V+(V-120)*2010
 
  • #3
ok that good 2 know, and where 2 go from here
 
  • #4
gneill
Mentor
20,793
2,773
Ask yourself what V represents (after all, you wrote the equation!). Compare with what the problem is asking you to find out.
 
  • #5
im realy stuck, i dont know please give me a hint
 
  • #6
gneill
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20,793
2,773
Go back over your derivation of the equation. What was V for?
 
  • #7
velocity
 
  • #8
gneill
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Which velocity?
 
  • #9
the travling velocity
 
  • #10
gneill
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  • #11
the space vehicle
 
  • #12
gneill
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the space vehicle
Surely that's what the "1200" is on the left hand side of the equation?
 
  • #13
yees
 
  • #14
gneill
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2,773
  • #15
i aint got a clue, is it for the heavier body velocity
 
  • #16
gneill
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You need to be sure if you are to understand how to do these sorts of problems.

What physical law allowed you to write the equation in the first place?
 
  • #17
dllamberts principle
 
  • #18
gneill
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dllamberts principle
Not quite. There's a particular conservation law involved here.
 

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