Centripetal acceleration of Earth around Sun

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Homework Help Overview

The problem involves calculating the centripetal acceleration of the Earth as it orbits the Sun, assuming a circular orbit with a radius of 1.5e11 m and a period of one year.

Discussion Character

  • Exploratory, Mathematical reasoning

Approaches and Questions Raised

  • The original poster attempts to calculate centripetal acceleration using the formula a = (v^2) / r, deriving the velocity from the orbital period. Other participants confirm the calculations and suggest alternative methods for verification.

Discussion Status

Participants generally agree that the calculations appear correct, with some offering alternative approaches to verify the result. There is an ongoing exploration of different methods to arrive at the same conclusion.

Contextual Notes

Some participants note that the values used for gravitational force and mass are approximations, which may affect the accuracy of the alternative method suggested.

blue5t1053
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Problem:
The Earth's orbit (assumed circular) around the sun is 1.5e11 m in radius, and it makes this orbit once a year. What is the centripetal acceleration of the earth?

Equations:
a = (v^2) / r
T = (2*pi*r) / v

My work:
T = (2*pi*r) / v;

1 year = (365 days / 1 year)*(24 hours / 1 day)*(60 mins / 1 day)*(60 secs / 1 min) = 3.1536e7 s;

3.1536e7 s = (2*pi*1.5e11 m) / v;
algebraically rearranged is: v = (2*pi*1.5e11 m) / (3.1536e7 s)
v = 29885.8 m/s

a = (v^2) / r;

a = ((29885.8 m/s)^2) / (1.5e11 m);
a = 0.005954 m/s^2 MY ANSWER

My question is if this is correct? I've been bombarded with tough questions up until this one and I am curious to know if I solved this correctly. It 'seemed' too easy. Confirmation on the answer would be appreciated since I can't find any information on presumed circular rotation around the sun. Thank you.
 
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Looks OK to me.
 
I haven't plugged the numbers in but your working is correct.
 
The answer looks right. An alternative way of solving this question (to check your answer) would be to just ask what is the centripetal acceleration of Earth around the sun, given the sun's gravitation force at our distance.

acceleration=G*m1/r(2)

G=gravitational constant=6.67E-11 m(3)kg(-1)s(-2)
m1=mass of sun (1.00 E30) kg
r=distance to the sun = 1.5E11 m

Ie. acceleration = 6.67E-11 m(3)kg(-1)s(-2) * (1.00 E30) m / [ (1.5E11 m) * (1.5E11 m)]

Answer = 5.8987E-03 ms(-2)

My mass of distance were approximations, but the answer is very close indeed.
 
Last edited:

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