Math Is Fun Forum

Identity

Member

Registered: 2007-04-18

Posts: 934

Physics problem, hard but nice

An astronaut is marooned from his spaceship in the Dagobah system. He is at a distance x from it. He has a mass of M He has a tank of oxygen of mass m and he breaths at a rate R kg/second.

He can use the oxygen to get himself back to the spaceship. Oxygen will squirt out of his tank into space with a speed of v. If he uses too much oxygen he will move quicker, but may not be able to breathe; if he uses too little he will get back too slowly and may also run out of oxygen to breathe. He is only allowed one squirt which expels a mass Δm of oxygen.

Assume that m << M (i.e. M + m = M)

Find the possible values for m in terms of the other variables so the astronaut will make it back to the ship.

In terms of the variables, what is the greatest distance (X) he can be from the spaceship and still survive?

If you want I may post a solution later on

Last edited by Identity (2008-03-04 18:50:42)

mathsyperson

Moderator

Registered: 2005-06-22

Posts: 4,900

Re: Physics problem, hard but nice

Edit:

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Why did the vector cross the road?
It wanted to be normal.

Identity

Member

Registered: 2007-04-18

Posts: 934

Re: Physics problem, hard but nice

Bravo mathsyperson! That is Correct!

Would you mind posting your solution? By the way I changed the first question so that the solution is less clunky.

Last edited by Identity (2008-03-04 18:52:13)