# Thread:

1. ## Speed of the Earth around the Sun.

"The Earth revolves around the sun in an elliptical orbit, however for this problem you can assume that the orbit is circular with a radius of 9.3 * 10^7 miles.

In what speed in feet per second does Earth travel around the sun?"

I know this problem has something to do with angular velocity, but I'm confused as to how to start solving the problem.

2. ## Re: Astronomy problem

Maybe you can use the formula:
$v=\frac{2\pi R}{T}$

with $R$ is the radius of the circle and $T$ the period.

3. ## Re: Astronomy problem

Originally Posted by explodingtoenails
"The Earth revolves around the sun in an elliptical orbit, however for this problem you can assume that the orbit is circular with a radius of 9.3 * 10^7 miles.

In what speed in feet per second does Earth travel around the sun?"

I know this problem has something to do with angular velocity, but I'm confused as to how to start solving the problem.
1. You have to determine the circumference of a circle with a radius of approximately 93.000.000 miles. Convert the result into feet. (I've got 3085295313240 ft but of course the pretended accuracy of this number is ridiculous)

2. You are asked to find the duration of one year. There are a lot of different "years" in astronomy. I would take the tropical year. According to Wikipedia (have alook here: Year - Wikipedia, the free encyclopedia)
"The mean tropical year is approximately 365 days, 5 hours, 48 minutes, 45 seconds"
Convert this time into seconds (I've got 31,556,925 s)

3. Calculate the speed (I've got $v \approx \dfrac{3,085,300,000,000}{31,556,925}\approx 97770\ \frac{ft}s$ )
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