What Are the Equations for Calculating Centripetal Acceleration?

[SmallPub]

The radius of the Earth's orbit about the sun is about 1.5x10^11m. The mass of the Earth is 5.98x^10^24kg



Equations:
ac= v^2/r
ac=4∏^2/r
v=2∏r/T


I could not figure out what to do so i could not attempt it

 

[frensel]

Centripetal acceleration is $a_c=\frac{v^2}{R}$.
Since $v=\frac{2\pi R}{T}$, where $T$ is the period, so
$a_c=\frac{4\pi^2 R}{T^2}$.

 

[voko]

Your equations, except the first one, are incorrect. Find the correct equations first.