# The Earth takes one year to orbit the Sun at a distance of 1.5 x 10^11 m. Calculate i

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#1
The Earth takes one year to orbit the Sun at a distance of 1.5 x 10^11 m. Calculate its speed.

Speed = distance/time

(1.5 x 10^8)/ (365*24*60*60) = 4.75646... kms-1

Why is the answer in the book 29.9 kms-1?
0
10 years ago
#2
Because your title has to the power 11 and your working has to the power 8, maybe?

Either work in metres or km.
0
10 years ago
#3
distance is wrong. you've used the radius not circumference.

basically you've calculated what the average speed of the earth would be if it took a year to crash directley into the sun
1
10 years ago
#4
Like, really really fast.
0
#5
(Original post by DumpOrStay?)
Because your title has to the power 11 and your working has to the power 8, maybe?

Either work in metres or km.
I changed the distance to km because the answer in the book is given in km. If I do the same sum with x10^11 it's just 1000 x bigger
0
10 years ago
#6
i =
2
#7
(Original post by didgeridoo12uk)
distance is wrong. you've used the radius not circumference.

basically you've calculated what the average speed of the earth would be if it took a year to crash directley into the sun
Ah ok.

So the distance given is the radius? So the correct sum would be

(2 x pi x 1.5x10^8) / (365*24*60*60)

= 29.8857...

Yay

Thanks
0
10 years ago
#8
The motion is circular, so you must find the circumference of the orbit first.

Pi x diamter = 3.14 x (2x1.5x10^8)=9.24x10^8.

Then use speed = distance/time

Speed = 9.24x10^8) / (365x24x60x60)=29.885 kms^-1
0
1 year ago
#9
becos its the radius u need to find the circumference of the earth 2*pi*r
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