# Period of a spring in SHM (simple harmonic motion)

An object with unknown mass M is hanged on a vertical spring with unknown spring constant K, the spring is in rest and is 14 cm from its normal point (if it didn't had the mass hanged it had less 14 cm), the object is then slightly pushed in a form that initiates a SHM, i am then asked to determine the period T of its oscillation.

I'm lost for answers i think maybe i didn't understand the question and i'm missing something but i don't know what, thank you for the answers.

Assume this is on Earth, so you know $g$. Don't try to use any values for $M$ or $k$. Just use symbols. Draw a free-body diagram for the system at rest. From this you can get the relationship between $M$ and $k$ and $g$. You probably also have an expression telling you the relationship between the $T$, $M$, and $k$. Do the algebra and everything should work out.