# Homework Help: Cylinder with buoyency

1. May 29, 2017

### ehf

1. The problem statement, all variables and given/known data
A cylinder shape object with a movable piston is 1.5 times of its own weight. The mass of object is figure. The initial buoyant force of the object is the waterVt.41 R Pititon iri, cylinder is Vi. and P1. Ignore the net volume of the tinder aP Before floating in the water container as shown in the Ina, and the volume and pressure of air inside Piston 1 cylinder material. The pressure at the top of water After container is set to be 0. Assume the temperature is (1)SP is applied from an external syringe. (2) and (3) show shapes of the cylinder before and after applying so P. constant. (a) Find out the required ratio of length /2/11 to make the object start to sink. [2 points] (b) In a case that we ignore the pressure due to water depth, find the minimum pressure aP to be applied to the water in order to make the object sink. [4 points] (c) In a case that we consider the pressure due to water depth, find the minimum pressure a p to be applied to the water in order to make the object sink. [4 points]
http://i.imgur.com/iVok98y.jpg
Well im sorry but i have an exam coming up so what i can do is a simple OCR. if you click the imgur link it is perfectly visible.

2. Relevant equations
P=P0+ρgh
F=mg=ρgV
3. The attempt at a solution
1 and 2 is about it but i dont know whether to consider the l1 and l2 or the whole container.
again, this imgur link is good.
http://i.imgur.com/59Ew8vJ.jpg

2. May 29, 2017

### haruspex

As I posted before, your answers to parts a and b look fine, but the last part is unintelligible.
Take the trouble to type your working in and explain what you are doing.
That's why @Mark44 closed the thread.

3. May 29, 2017

### Drakkith

Staff Emeritus