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

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Homework Help Overview

The discussion revolves around calculating the time it takes for light from the Sun to reach Earth, with the distance to the Sun given as 1.5 x 10^11 meters. The subject area is physics, specifically focusing on concepts related to speed, distance, and time.

Discussion Character

  • Mathematical reasoning, Assumption checking

Approaches and Questions Raised

  • The original poster attempts to calculate the time using the speed of light but expresses uncertainty about the method. Some participants examine the units involved in the calculation and question the correctness of the approach. There are also inquiries about converting the time from seconds to minutes.

Discussion Status

The discussion includes attempts to clarify the calculation process and unit conversions. Some participants have provided guidance on unit cancellation and the implications of the calculations, while others are exploring different interpretations of the results.

Contextual Notes

Participants are working under the constraints of a homework assignment, which may impose specific requirements for the format of the answer (e.g., needing the result in minutes rather than seconds).

zachcumer
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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?
 
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Look at the units:

[itex]1.5 \cdot 10^{11} \,m \cdot \frac{ 1 s }{ 3 \cdot 10^8 \,m }[/itex]

Note that the meters cancel, leaving you with seconds.

If you divide it your way, you get:

[itex]\frac{ 3 \cdot 10^8 \, m }{ 1 s} \cdot \frac{1}{ 1.5 \cdot 10^{11} \,m}[/itex]

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

- Warren
 
so...
 
zachcumer said:
so...

Yes?

- Warren
 
I need it in minutes not seconds.?
 
so the answer is 5 times 10 to the 18?
 
zachcumer said:
so the answer is 5 times 10 to the 18?

No, you may need to review how to multibly and divide exponents.
 
so its 500 seconds...
 
zachcumer said:
so its 500 seconds...

Yes, that's correct.

- Warren
 

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