Final answer:
Gravity, air friction, and wind may decrease the reach of a solid fire stream by pulling it downward, slowing it down, and pushing it sideways, respectively.
Step-by-step explanation:
When considering how gravity, friction of air, and wind may act on a solid fire stream, it is important to note that these factors can impact the stream's trajectory and characteristics. Gravity exerts a downward force on the stream, causing its velocity to decrease as it rises and potentially reducing its reach. At the same time, air friction and wind can alter the stream's path and speed, which can lead to an increase in the stream's area as it falls due to the continuity equation, where the product of cross-sectional area and velocity must remain constant.
The correct answer to how these forces may affect a solid fire stream is B. They may decrease the reach of the stream. Gravity pulls the stream downward, reducing its height and reach, while friction of air can slow it down and wind can push it sideways, further impacting its intended direction and distance.