일반물리학 1 — Measurement: Problem 30

30 Water is poured into a container that has a small leak. The mass m of the water is given as a function of time t by \( m = 5.00t^{0.8} - 3.00t + 20.00 \), with \( t \ge 0 \), m in grams, and t in seconds. (a) At what time is the water mass greatest, and (b) what is that greatest mass? In kilograms per minute, what is the rate of mass change at (c) \( t = 3.00 \text{ s} \) and (d) \( t = 5.00 \text{ s} \)?