Understanding Fluids and Pressure: Basic Concepts and Problem-Solving Assistance

[benji]

Fluids--Pressure. Help needed...

I've read the chapter in my book on fluids but I'm still not understanding my homework... I have a few problems that are--from what I can tell--the basic concepts of what all of the other problems are based off of. If someone could tell me how I need to go about doing these, it would be a great help. I'm not asking you to do my homework for me; just point me in the right direction with examples/explanations on why what does what so I can understand this stuff a little bit better.

A cylinder (with circular ends) and a hemisphere are solid throughout and made from the same material. They are resting on the ground, the cylinder on one of its ends and the hemisphere on its flat side. The weight of each causes the same pressure to act on the ground. The cylinder is 0.500 m high. What is the radius of the hemisphere?

Some researchers believe that the dinosaur Barosaurur held its head erect on a long neck, much as a giraffe does. If so, fossil remains indicate that its heart would have been about 12 m below its brain. Assume that the blood has the density of water, and calculate the amount by which the blood pressure in the heart would have exceeded that in the brain. Size estimates for the single heart needed to withstand such a pressure range up to two tons. Alternatively, Barosaurus may have had a number of smaller hearts.

If someone could help me out with one or both of these problems, I'd really appreciate it! Thanks.

 

[Gokul43201]

1. Given : both exert the same pressure. What is the definition of pressure ?

2. How do you find the pressure in a liquid column, at some particular height ?

 

[benji]

P=F/A

...but the I would have F/A=F/A and I don't know anything for either side of the equation..?


...and number 2 I might be able to work out, I'll just have to give it some time...

 

[Gokul43201]

P=F/A

1. A = area of contact. What is the shape of this area in both cases ? What is the formula for the area of this shape ?

F = force. What is the force due to ? What is the formula for this force ?

2. Simply Googling "pressure in liquid column" will get you started, but really, this should be covered in your text.

 

[benji]

Thanks for the help.