Physics 309
			Midterm Exam
			6 March, 2002
			L. Weinstein


Part I:

What are the following values:
a) Earth-Moon distance (m)
b) Gravitational Constant (N-m^2/kg^2)


Part II:  Do ONE of the following three questions:  List your
assumptions explicitly please.  Show your work.  

1) How much energy would be released by the gravitational collapse of
   the sun from its present size to a sphere only 10 km across?  The
   mass of the sun is 2 x 10^30 kg.

2) What is the kinetic energy of a drifting continent?

3) How many blades of grass are there in a lawn the size of a football
   (or soccer) field?  What is the total mass of the grass
   (excluding roots)?