The How Long Does It Take for the Sun's Light to Reach Earth?

[zachcumer]

The Sun is 1.5 x 10^11 m from the Earth. How long does it take for the Sun's light to reach the Earth?

Above is the question I have to answer I was thinking...

300,000,000,000 meters/1.5*10^11...dunno?

 

[chroot]

Look at the units:

1.5 \cdot 10^{11} \,m \cdot \frac{ 1 s }{ 3 \cdot 10^8 \,m }

Note that the meters cancel, leaving you with seconds.

If you divide it your way, you get:

\frac{ 3 \cdot 10^8 \, m }{ 1 s} \cdot \frac{1}{ 1.5 \cdot 10^{11} \,m}

which has units of 1/s. This isn't a unit of time, so it's not what you want.

- Warren

 

[zachcumer]

so...

 

[chroot]

so...

Yes?

- Warren

 

[zachcumer]

I need it in minutes not seconds.?

 

[zachcumer]

so the answer is 5 times 10 to the 18?

 

[Integral]

so the answer is 5 times 10 to the 18?

No, you may need to review how to multibly and divide exponents.

 

[zachcumer]

so its 500 seconds...

 

[chroot]

so its 500 seconds...

Yes, that's correct.

- Warren