7. An object with mass m is dropped from rest and we assume that the air resistance is proportional to the speed of the object. If s(t) is the distance dropped after t seconds, then the
speed is v=s'(t) and the acceleration is a =v'(t). If g is the acceleration due to gravity, then
the downward force on the object is mg - cv, where c is a positive constant, and Newton's
Second Law gives
dy
-=mg - CV
dt

(b) What is the limiting velocity?
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