A mass of 50.00g hangs from a 7.00cm-long spring that is rigidly attached to a ceiling. The mass is pulled down slightly, let go, and is observed to make 8 round trips (up and back down) in 14.00s. What is the stiffness constant for this spring

0.645 N/M

Explanation:

Given

Mass=50.00g

We have to convert into the kg

So Mass =0.050 Kg

We know that

........................Eq(1)

Where T= time

and M= Mass

K= Stiffness constant

On squaring both side we get

....Eq(2)

Putting the value of M ,T and π in Eq(2) we get

K=0.645 N/M

it is the second option.