I have struggled with this question. I don’t understand what do especially that the question says inelastic but there is a spring.

A mass of 12 kg is sliding along a frictionless surface at a speed of 5 m/s.

It collides perfectly inelastically with a stationary mass of 24 kg which is attached to

a spring. If the spring constant is 225 N/m, where are the stuck-together masses 3

seconds after the collision?

I know momentum before collision is 12*5= 60

But I don’t know what to do from here … I know momentum has to be conserved but not energy but I am having trouble understanding what can the next step be.

I hope someone can help me.

http://ift.tt/1ivkqXP