Find Spring Position After Attaching 2.7kg Mass

[bosox3790]

A spring with k = 47 N/m hangs vertically next to a ruler. The end of the spring is next to the 15 cm mark on the ruler. If a 2.7 kg mass is now attached to the end of the spring, where will the end of the spring line up with the ruler marks?

I got the answer to be 141 cm because I thought that the 15cm is to be converted into meters, can anyone help me with this question?

 

[stunner5000pt]

yes the cm should be converted to metres

what is the extension as a result of the mass being attached?

 

[bosox3790]

I got 141 cm but that's not correct. I can't figure out the correct answer.

 

[stunner5000pt]

I got 141 cm but that's not correct. I can't figure out the correct answer.

how did u get that?

 

[bosox3790]

I used 0+mg(0.15m + change in y)=0+ .5k(change in y)^2