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I was sitting in a spa hot tub and some chute coming down from a chute was hitting my knee.

I'm wondering 2 things

  • a) How do I calculte how high the water goes when it hits my knee
  • b) How much water does it takes before my knee start moving.

Let's say the water move at $1\over2 m/s$

for B I got

The water flow is about 60 cm large and 4 cm of height

$M = $ 240 Cubic centimeters = 0.24 Kilograms $F = $ $0.24 \cdot $ $1/2 m/s \over 1 second $

right?

edit: why do you tagged this as a homework. geez. I'm trying to introduce myself to physics with some random real world situation. Just want to know want should I use to calulate.

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Hi Dave. Welcome to Phys.SE. I'm closing this as too localized. I'm happy to reopen it if you (or someone else?) could turn it into a coherent conceptional question cf. our faq. – Qmechanic♦ Dec 14 '12 at 22:42
2  
If a blob of water hits a vertical plate, some will splash up, and some will splash down (if the 3rd dimension can be ignored). Before hitting the plate, it has a certain momentum in the vertical direction. After hitting the plate, the part going up and the part going down each have their own momentum. If you sum those two, they are the same as the initial vertical momentum. That plus conservation of energy allows you to tell what velocity the upward splash has, and therefore how high it goes. – Mike Dunlavey Dec 15 '12 at 4:19
@Dave: 1) Your edit v3 should have been a comment. 2) Concerning homework tag, see also here. Note that it doesn't have to be actual homework to be labeled with homework tag. – Qmechanic♦ Dec 15 '12 at 10:38

closed as too localized by Qmechanic♦ Dec 14 '12 at 22:43

This question is unlikely to help any future visitors; it is only relevant to a small geographic area, a specific moment in time, or an extraordinarily narrow situation that is not generally applicable to the worldwide audience of the internet. For help making this question more broadly applicable, see the FAQ.

1 Answer

up vote 0 down vote

Water is sticky and so your rule does not apply. Most likely the water will just bend around your knee... There is no way to calculate what you are asking.

As for the "how long till your knee moves", that depends on your knee's size, weight, etc.

Why do you want to know anyway?

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Well, the water is not sticky, my knee is outside the hot water. A chute outside the hot tub has a water flow of 1/2 m/s and when it hits my knee, it goes up in the air. I want to know how to calculate how high the water will get depend on the speed it goes. Why are you angry ? Just asking for fun. chill out. – Dave Dec 14 '12 at 22:33

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