## anonymous one year ago n astronaut having mass 320 kg with equipment included is attempting an untethered space walk. The astronaut is initially at rest with respect to the nearby spacecraft, but discharges 30.0 g of nitrogen gas at 900.0 m/s from a portable propulsion unit. How fast is the astronaut moving after doing that? 0.36 m/s, 0.084 m/s , 27 m/s, or 84 m/s ?? :/

1. Michele_Laino

here we have to apply the momentum conservation law

2. anonymous

ok!

3. Michele_Laino

so we can write this: $P = 0.03 \times 900 = ...$ is the momentum of the gas discharged

4. Michele_Laino

oops..discharged gas

5. Michele_Laino

how much is P?

6. anonymous

errr 27?

7. Michele_Laino

ok!

8. Michele_Laino

the momentum gained by our astronaut is: $P' = 320 \times V$ where V is his velocity

9. Michele_Laino

so we can write: $27 = 320 \times V$ what is V?

10. anonymous

0.984375? so our solution is 0.084 m/s ?

11. Michele_Laino

$V = \frac{{27}}{{320}} = {\text{0}}{\text{.084375}}$

12. Michele_Laino

so V=0.084

13. anonymous

so is that our final solution? :O

14. Michele_Laino

yes!

15. anonymous

yay!! thank you!!

16. Michele_Laino

thank you!! :)