Momentum After Inelastic Collison

[NatalieWise123]

Homework Statement

Two hockey pucks are sliding across the ice in the same direction. One has a momentum of 35 kg*m/s. The other has a momentum of 7 kg*m/s. After the collision, the pucks stick together. What is the momentum of the pucks after the collision?

Homework Equations

The Attempt at a Solution

I'd think you'd just add them together because of the Law of Conservation of Momentum but for some reason I'd imagine they'd slow down after hitting. Is 42 kg*m/s the right answer and if so why?[/B]

 

[J Hann]

Even though energy is not conserved in an in an inelastic collision,
momentum is conserved.
So write an equation for conservation of momentum and solve for the final speed.
Remember, you now have a final mass of 2 m.