How Long Does It Take Astronaut Jane to Drift Back to Her Spaceship?

[Mowgli]

Homework Statement

Astronaut Jane's lifeline to her spaceship comes loose and she finds herself stranded, "floating" 75.0m from the spaceship. She throws her 2.00kg wrench at 20.0m/s in a direction away from the ship. If she and her spacesuit have a combined mass of 175kg how long does it take her to coast back to the spaceship?

Homework Equations

The Attempt at a Solution

This one I am so lost about...

Do I use the equation: (Mass of Suit x Mass of Jane) Initial Velocity + Mass of wrench (Initial Velocity) = (M of Suit + M of Jane) (V 1 + M of wrench (V 1 of wrench)

Therefore = (175kg) 0 + 2kg (0) = (175kg) (final velocity + 2kg (20.0m/s)

 

[bp_psy]

All is good to this point.

 

[Mowgli]

Do I have to factor in the fact that she floated 75 m away?

 

[bp_psy]

Do I have to factor in the fact that she floated 75 m away?

That does not influence conservation of momentum.

You only need the distance to find the time it takes to get back to the ship.

 

[Mowgli]

Homework Statement

Therefore = (175kg) 0 + 2kg (0) = (175kg) (final velocity + 2kg (20.0m/s)

then 0=175(final velocity) + 40

final velocity = -40/175
= -0.23 m/s ??

 

[collinsmark]

then 0=175(final velocity) + 40

final velocity = -40/175
= -0.23 m/s ??

Looks okay so far.

 

[Mowgli]

what else needs to be done?

 

[collinsmark]

what else needs to be done?

You need to find out how much time it takes for someone to travel 75.0 m when traveling at a speed of 0.229 m/s.