# please help with one question, i do not know what to do?

During the course of its hydrogen-fusing lifetime, approximately 0.065% of the Sun’s mass (2 × 1030 kg) is converted to energy. If the Sun loses mass at a rate of 4 billion kilograms each second, calculate the approximate hydrogen-burning lifetime for the Sun

### 2 Answers

- .Lv 61 decade agoFavorite Answer
The fusion reaction occurs in the sun's core (1.99 x 10^30 kg).

Thus at a hydrogen fusion rate of 4 x 10^9 kg/s, the sun will burn in the main sequence for: -

t=(1.99 x 10^30x0.00065)/4 x 10^9 seconds

or

about 1.025 x 10^10 years (10 billion years).

I hope this helps!

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- getfreducatedLv 61 decade ago
Take .065/100 = .00065 and multiply by the mass of te sun. This is how many Kg will be burned.

Divide by 4 billion Kg to get the life of the sun in seconds.

From there, convert to more "friendly" time units.

-Fred

EDIT: Are you saying sun's mass is 2 * 10^30 Kg (I don't have a book handy)?

If so...you get 3.25 10^17 sec = about 10 billion years

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