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**Question about momentum and larger masses (ice tubing, and why we have to let go)**

Okay, so my friends and I went snow tubing recently where the track was as such:

_

..\

...\<---hill

....\.............................................../

.....\............................................./<---stopping end hill

......\___________________________/

Where the hill at the end is to slow you down and stop you.

The people there instructed us that if we were going as a group, to let go of each other's tubes, before reaching the speed bump because if we stayed together as a group, our speed would be much greater, and will throw us over the end.

This is where I'm confused. It seems to me that there would be no difference whether or not you stayed as a group. My reasoning being:

Assume there are 3 people, each with a mass of 1kg

After going down the hill, the 3 people as a single mass, M, has a velocity of 2m/s

Then p=M[tex]v_{1}[/tex]=6kgm/s

After splitting apart, momentum is conserved,

so p=(m[tex]v_{2}[/tex]) + (m[tex]v_{2}[/tex]) + (m[tex]v_{2}[/tex])

Which results in each person having the same velocity as before, 2m/s.

Now, assuming a frictionless surface, the only thing slowing down the tubers would be the hill at the end: the force of gravity. Which would slow down the tuber at a rate of g*cos[tex]\vartheta[/tex], regardless of the mass.

Therefore, regardless of whether the 3 tubers stayed as one group or not would not make a difference in how far up the hill they go at the end.

**Is my argument sound?**

Also, in the practical setting, I did observe that the ones who stayed together as a group really did go further up the hill than the ones who split apart though.

The reason for this that I can come up with is that friction is somehow the culprit. but no matter what, my friend keeps believing that the reason has something to do with momentum and how the single tubers only have a momentum of 2kgm/s, while the group has 6kgm/s, and so the group is more difficult to slow down.

**Is he correct or am I?**

In either case, could someone explain why?

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