Short Answer 
The steps outline the understanding of sinusoidal functions as models for periodic oscillations, highlighting their smooth cycles. Specifically, it focuses on a scenario where the height of a point decreases from a peak to a minimum between two time points, along with a decreasing rate of change in height during this interval.
Step 1: Understand Sinusoidal Functions
Sinusoidal functions model smooth, periodic oscillations like the height of a rotating windmill blade. These functions are characterized by their harmony and repeating cycles, providing a great tool for understanding periodic phenomena.
Step 2: Analyze the Interval Between t1 and t2
During the interval from time t1 to t2, the height (h) of point B is both positive and decreasing. This typically occurs after the function reaches its peak height, at which point the height starts to drop before reaching a minimum. This illustrates the behavior of sinusoidal functions as they progress through their cycles.
Step 3: Rate of Change of Height
In the interval between t1 and t2, the rate of change of height (h) is also decreasing. This means that as the height decreases, the speed at which it decreases is slowing down until it reaches its minimum point, consistent with the properties of sinusoidal functions.