Solve Physics Problem: 500m from Safety of Space Craft, 11.32min Air Left

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Homework Help Overview

The problem involves a scenario where a space person is 500 meters away from a spacecraft with a limited air supply of 11.32 minutes. The individual throws a phaser to propel themselves back, and the question seeks to determine how many extra minutes of air they might have as a result of this action.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • The original poster attempts to apply conservation of momentum to find the velocity of the person after throwing the phaser. They express uncertainty about their calculations and whether they have made an error. Other participants question the calculations and suggest that the mass of the phaser should be considered in the momentum calculations.

Discussion Status

The discussion is ongoing, with participants providing feedback on the original poster's calculations and questioning the assumptions made. Some participants suggest that the original poster may not have made a mistake, while others point out potential oversights in the calculations.

Contextual Notes

There is a lack of clarity regarding the calculations performed by the original poster, particularly in how they accounted for the mass of the phaser in relation to the person's momentum. The problem also implies a trick question aspect, which adds to the uncertainty in interpretation.

antiflag403
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Ok. This one is giving me some trouble:

A space person is motionless a distance of 500.0 m from the safety of the space craft. The person has exactly 11.32 minutes of air left, and the person's mass is 103.2 kg including the equipment. The person throws a phaser (for all you Trekkies) at a velocity of 50.2 km/h away from the spacecraft in order to get back. If the mass of the phaser is 5.3 kg, how many minutes of extra air does the person have?

Heres what i have:
I found the momentum of the phaser to be 73.67 Kgm/s
Then the momentum of the person must also be 73.67 because of conservation of momentum.
Solving for the velocity of the person you get -.7139... inputing this into v=d/t, i get t= 700.38s.

I think i may have made an error, or missed something because the question says how many minutes of extra air does the person have, and 11.32 m of air is 679.2 s, which is less than my t. therefore there is no extra air.
Am i doing something wrong? or is it a trick question?
Thanks a lot for any help
 
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Looks good to me...
I think your teacher just WANTS you to think you made a mistake; teachers do that...
 
I think he has about 0.25 minutes of air left! :-)
 
Last edited:
Christina De Rose said:
Looks good to me...
I think your teacher just WANTS you to think you made a mistake; teachers do that...

I think teachers want you to think! :smile:
 
It's hard to tell what error you made, if any, since you didn't tell us how you calculated those numbers. Did you remember to subtract the mass of the phaser from the mass of the spaceman?
 
No, that's what he was doing wrong, judging by his anwers. You get approx. Tide's answer if you include that. Problem solved.
 

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