Phizz Quizz No 4

[knotman]

Here we go again, since the BB is quiet.

Well known sea kayaker Sonja Kelly is practising rolling in a small pool. Sitting in her kayak her friend notes that that the water level is at a certain mark on the side of the pool.
When Sonja rolls over and stops in a hang down position, (body fully under the water, still in cockpit) will her friend see the water level rise, fall or stay the same? Ignore any small waves. :unsure: Sennen

[BillyDennigan]

I\'d say the rule that \'A floating object will displace its own weight in a fluid.\' means that the water level will stay the same. It doesn\'t matter whether the object is upside down or right way up.

In this case you might expect that since Sonja is now under the water, more water would be displaced. In fact this is true, but since she is no longer upright in her boat, she is no longer exerting the same downward force on it, so it now displaces less water, exactly cancelling out the effect of the unfortunate upside down paddler.

Billy.

[DaveWalsh]

Did she draw a deep breath before capsising ?
DWalsh

[martinguilfoyle]

my head hurts!!!!!!!!!!!
martin

[knotman]

Any more thoughts out there? Ain\'t saying nothing yet. Soon.
Admin: that was a great answer last post. Any more?

Dave: Would taking a deep breath make any difference anyway?

Martin: A dull ache between the ears when some people think is perfectly normal. Don\'t worry about it. It lessens with practise. :laugh:

Sennen :ermm:

[DaveWalsh]

The rule about the apparent loss of weight equalling the loss of displaced liquid must have its limits. If Sonja takes a deep breath, she will be positively buoyant under the water but if she doesn’t she will be negatively buoyant (try it, hold your breath and you float, exhale and you sink). If Sonja is negatively buoyant the levels will stay the same for the reasons given by Billy Dennigan. But if she takes a deep breath …..
DWalsh

[DaveWalsh]

All right, Sennen, all right.
It would appear I may not be absolutely 100% correct?
I would be much more candid perhaps, except for the three peculiar new rules of conduct that I observe seem prevalent nowadays in ISKA :
1. It is forbidden ever to admit you are wrong.
2. Never apologise even when having done wrong has hurt someone.
3. When forced to break rule 2, use the occasion to twist the knife a little more.
They aren\'t my rules or rules I like, but when in Rome and all that....
I\'ll try to answer Phizz Quizz 5 a little better, promise.
DW

[Dermot]

Sennan, Dave - thanks for the final practical clarification. It sounds like you are suggesting we should seal this famous Sonja upside-down in a kayak, using a cannon ball, in a small pool in Rome, with 147kg of air?!?

[ciaranclissmann]

You\'re all missing the point.

Sonja Kelly, and her alter-ego Kelly Sonjas (Eurovision starlet from Lestovia), both own bright yellow Kokataaaat!! drysuits with GORETEX written all over them. So right way up or upside down, it just doesn\'t matter.

Ciaran