## viniterranova 3 years ago A astronaut has 100 kg of mass. Unfortunately the mass of his body was spread out in a sphere. After that, the density inside the sphere is 2x10^-28 kg/m^3. What is the radius of the sphere where the mass of the astronaut was spread out?

1. sauravshakya

Density = MASS/VOLUME

2. sauravshakya

use it to find the volume of the sphere

3. viniterranova

I just set up the following relation 6x10^-28=100kg/V

4. sauravshakya

Yes u r correct. PLZ CONTINUE

5. viniterranova

So, with some algebric manipulation i found this relation V=1x10^2/6x10^-28 and i got V=1/6x10^30.

6. viniterranova

I think this is the volume of the sphere.

7. sauravshakya

Now, Volume of a sphere=4/3 pi r^3

8. sauravshakya

Use it to find r

9. viniterranova

I just plug it in the formual, right?

10. sauravshakya

YEp, 1/6x10^30 = 4/3 pi r^3

11. sauravshakya

got it?

12. viniterranova

Just one moment.

13. viniterranova

i got 1,46459

14. sauravshakya

But I got different

15. viniterranova

What do you got?

16. viniterranova

i write the equation in this order. cubic root of 1/6x10^30=4/3phi*r

17. viniterranova

Now i got 4,12740906x10^9 m

18. sauravshakya

Density= MASS/ VOLUME 2x10^-28=100/VOLUME VOLUME=50 * 10 ^28 4/3 pi r^3 = 50 * 10^28 r^3=4923725109

19. viniterranova

That ´s right.

20. sauravshakya

r=4923725109

21. viniterranova

How do u calculate the 2x10^-28=100/VOLUME. Plz do it step by step.

22. sauravshakya

DEnsity =MASS/ VOLUME

23. sauravshakya

Now, substitute the given values

24. viniterranova

thanks

25. sauravshakya

:)yw

26. viniterranova

But sorry i can´t understant how do you calculate 2x10^-28=100/VOLUME. May you do it plz?

27. viniterranova

When i calculate V i have found 50/3x10^28. How did you got 50 * 10 ^28. PLz.

28. sauravshakya

100/2 =50 right?

29. viniterranova

Yes, but where did you find the number two? If we have the division 100/6?

30. viniterranova

Did you divide 6/3. I got it. now.