# Homework Help: Hockey puck velocity help

1. Nov 27, 2007

### skins266

A 0.105 kg hockey puck, moving at 35.0 m/s, strikes a 0.240 kg octopus thrown onto the ice by a hockey fan. The puck and octopus slide off together. Find their velocity in m/s

I really do not have a clue on what to do and how to do it.

2. Nov 27, 2007

### Shooting Star

I'd think that the octopus will throw the puck at the offending fan, seeing that he was to blame in the first place, to get the poor octopus get hit by the puck. With the force of eight arms behind it, it'll pack a pretty punch. Serves him right.

Getting back to Physics, the sum of the initial momenta of puck and poor octopussy will be equal to the final momentum of the two together. You know initial masses and speeds, and the total mass, so it shouldn't be problem.

Last edited: Nov 27, 2007
3. Nov 27, 2007

### skins266

Yeah, we get some pretty weird descriptions, but it makes it fun.

So basically I add the two masses and then find the impusle of the puck hitting the octopus and then I multiply that by the two masses?

4. Nov 27, 2007

### Shooting Star

M_puck*v_puck + M_oct*v_oct = Mtotal*v_final.

That's conservation of linear momentum.

5. Nov 27, 2007

### skins266

Thanks for your help. I knew it was something like that.

6. Nov 28, 2007

### Bill Foster

An octopus?

Good grief.

http://www.turboconnection.com/images/picard.jpg [Broken]

Last edited by a moderator: May 3, 2017