What is the amplitude of the subsequent oscillations?

[alex_bwls]

A 375 g air-track glider attached to a spring with spring constant 9.50 N/m is sitting at rest on a frictionless air track. A 425 g glider is pushed toward it from the far end of the track at a speed of 96.0 cm/s . It collides with and sticks to the 375 g glider.a)What is the amplitude of the subsequent oscillations?

b) What is there period?

What formulas should I use, I don't seem to be using the right one.

 

[alex_bwls]

i think i figured the first part out

.5(0.8)(0.51)² = .5(9.5)A²

and now i can get the second part

period = 2pi* sqrt(m/k) = 2pi * sqrt(0.8/9.5) = 1.686 s