Final answer:
To stop Tom from falling before hitting the river below the bridge, he could grab onto a tree branch, land on a ledge, be caught by a safety net, with the fictional addition of being able to fly. In historical and real scenarios, tree branches and snow drifts have played roles in reducing the impact force for airmen during falls in World War II.
Step-by-step explanation:
The question revolves around the concept of forces and motion in the context of a person's sudden halt during a fall. In the scenarios provided, different methods are described that could stop someone from continuing to fall: grabbing a tree branch, landing on a ledge, being caught by a safety net, or the fantastical ability to fly. In real cases, such as with airmen in World War II, survival from free falls sometimes occurred due to the deceleration provided by tree branches and snow drifts reducing the impact force. This deceleration can be calculated by considering the change in velocity and the distance over which the change occurs. Moreover, when considering why a squirrel can jump from a tree branch without harm but a human might sustain injuries, it's important to consider factors like the body mass and structure differences, as well as the different impact energies involved.