B) At the time t1 when y(t1 ) = 0f t, x(t1 ) = 13f t, and, hence, dy/dt(t1) = -39/0 = -f t/sec (i.

B) At the time t1 when y(t1 ) = 0f t, x(t1 ) = 13f t, and, hence, dy/dt(t1) = -39/0 = -f t/sec (i.e., the top of the ladder will hit the ground with the infinite speed We constant speed which is not physically possible). Problem 4. Coffee is draining from a conical filter into a cylindrical coffeepot at the rate of 10 in3 /min. How fast is the level in the pot rising when the coffee in the cone is 5 in deep? How fast is the level in the cone falling at that moment?