Question: Suppose w is the weight of a stack of papers in an open container, and t is time. A lighted match is thrown into the stack at time t = 0.
(a) What is the sign of dw/dt for t while the stack of paper is burning?
(b) What behavior of dw/dt indicates that the fire is no longer burning?
(c) If the fire starts small but increases in vigor over a certain time interval, then does dw/dt increase or decrease over that interval? What about |dw/dt|?