Problem 2.36 (the Galileo problem).
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First, convert pounds (lb) to kg!  
Then you can get v_term for both masses.

Since the masses are dropped from rest, you
can use eq. 2.58 to get the times.  Which
mass hits ground first?  Where is the other 
mass at that time?   

Problem 2.40
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You should already be looking at a differential
equation like this:
   m dv/dt  = -bv -cv^2

This can be solved by separation of variables.

The resulting equation might be somewhat perplexing.
Try making a substitution of the type X = v/(b+cv).