1. Mar 11, 2007

### bmack

The speed of light is 3.0 x 10 exponent8 m/s. How Many minutes does it take for light to reach the earth from the sun. Which is 1.5 x 10 exponent11 m away?

I know the formula is t=d/v
so ?=1.5 x 10 exponent11 m /3.0 x 10 exponent8 m/s

The answer is 500s=8.3min....I just don't know how to get this darn anwer and I am about to so please give me a clue

I am doing the steps but coming out with a different answer.

2. Mar 11, 2007

### Staff: Mentor

So far, so good. How did you do that caculation? (Hint: Handle the exponents separately.)

3. Mar 11, 2007

### bmack

I know what the formula is however, when I apply it I do not get the same answer that is in the book the The answer is 500s=8.3min is inthe answer key at the back pf my book...

Okay so I need to handle exponents separate. okay, I am getting 50exponent3 because when you divide exponents you subtract. I still need another clue.:uhh:

4. Mar 11, 2007

### Staff: Mentor

The exponent 3 is correct (which stands for $10^3$), but what is 1.5/3.0? It's not 50!

5. Mar 11, 2007

### bmack

it is 0.5 right?

6. Mar 11, 2007

### hage567

Yes, that's right.

7. Mar 11, 2007

### Staff: Mentor

As hage567 already confirmed, you got it. Now put it together: 0.5e3

What's that equal to in plain old numbers (without the exponents)?

Last edited: Mar 11, 2007
8. Mar 11, 2007

### Saketh

One thing that you should understand, bmack, is that you knew how to do the physics, but the math gave you some trouble. I think it's helpful in learning physics to keep the two things separate, and to know which half (the physics or the math) is giving you problems.

So good job! You got the physics part of the question right (identifying the distance-time equation). The rest is just plugging through the mathematics.

9. Mar 11, 2007

### Staff: Mentor

Good point, Saketh!

10. Mar 11, 2007

### bmack

duh!!!!!!!I can't believe it!!! 0.5 exponet 3 is 500 I see that I do have a problem with the math more than anything because I am trying to convert the 500 into minutes but I am still lost.:yuck: I know .

Okay 500/60 is 8.3 right because there are 60s in a minute I can't believe It took me this long to figure out.

thank you all. I guess I am not as dumb as I thought I was:tongue: