Fluids and Solids

Question 1

How many Pa in 1 atm?

Answer 1

1.013 x 10^5 Pa = 1atm

Question 2

Shortcut to find how much of a floating object will be below water

Answer 2

The specific gravity tells how much. E.g. ice has sg of 0.92, so 92% will be below surface.

Question 3

Difference between cohesion and adhesion in liquids

Answer 3

Cohesion = attractive forces between molecules of same liquid (surface tension).
Adhesion = attractive forces between molecules of liquid and another substance (water droplets on windshield)

Question 4

Critical velocity for a fluid

Answer 4

Vc = Nr n/pD (Nr = reynold’s #, n is viscosity, p is density, D is diameter of tube)

Question 5

Bernoulli’s equation

Answer 5

P + pv^2/2 + pgy = P + pv^2/2 + pgy (absolute pressure + dynamic pressure stays constant, essentially conservation of energy)