#### Dragoon

The earth has an orbit of radius 148 million km around the sun. What is the speed of the earth on this orbit?

dont know how to do it i have used a couple of different formulas and havent gotten it right can anyone help?

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#### Nylex

Can you not use v = rω and the fact that ω = 2π/T?

#### NateTG

Homework Helper
Dragoon said:
The earth has an orbit of radius 148 million km around the sun. What is the speed of the earth on this orbit?

dont know how to do it i have used a couple of different formulas and havent gotten it right can anyone help?
How long does the earth take to make an orbit around the sun?
What distance does the earth travel in an orbit?
(Since the problem tells you that the orbit has a radius you can probably safely approximate the orbit with a circle of the appropriate radius.)
Then you can find speed using $$s=\frac{d}{t}$$ although you might want to do some unit conversion.

#### bchl85

NateTG said:
How long does the earth take to make an orbit around the sun?
What distance does the earth travel in an orbit?
(Since the problem tells you that the orbit has a radius you can probably safely approximate the orbit with a circle of the appropriate radius.)
Then you can find speed using $$s=\frac{d}{t}$$ although you might want to do some unit conversion.
Period T = 365 days = ... seconds.
Then using formulae which Nylex gave.

#### UrbanXrisis

What is the speed of the earth on this orbit? 30km/s

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