Physics CS 33
Set # 2
Spring 2006
Due date Wed. April 19th
Read HR&K:
Chapter 16
Read K&K: None

HR&K Problems Chapter 15   Problem 19
Chapter 16   Problems  3,  4,  8,  11,  14,  15
K&K Problems:
None

1. A raindrop has a mass of one gram.  Assuming it is perfectly spherical, find the pressure of the water inside the raindrop.  Use 1000 kg/m3  for the density of water and ignore the variation of pressure within the drop due to gravity.  You will have to look up the surface tension of water.

2. Consider the "Laplacian operator"   (i.e. the divergence of the gradient)

a) Write out the Laplacian of φ in Cartesian coordinates.

b) Using index notation, show that if φ is a "velocity potential" for an irrotational flow.

3. Consider the "water-pressure car" shown below:



Initially, the depth of the water is H.   Assume A1 >> A2 , so the speed of water inside the tank is small.

a) Find the thrust force as a function of h, the depth of the liquid at any instant.

b) When all the water has drained out of the tank, what will the speed of the car be?