I have calculated the spring constant to be 1.47N/0.050m = 29.4 N/m

The first stage is when the putty is falling down or:

Vp2 = sqrt(0.6*g)

Then I'm not sure. Can I say that momentum is conserved during the collision of the putty and frame?

The last stage would be conservation of energy when putty and frame travel downwards. But I need to know the total speed.

Could someone please give me a hint