Final answer:
When a child trips and falls forward, their reaction to this action can be described by Newton's third law of motion. By instinctively applying this law, the child's outstretched arms experience a reaction force from the ground that helps them to land more safely and prevent a direct impact on their body.
Step-by-step explanation:
Newton's Third Law of Motion
When a child running in the playground trips and falls forward, the reaction to this action can be described by Newton's third law of motion. According to this law, for every action, there is an equal and opposite reaction. In this case, when the child pushes their arms forward to break the fall, the ground exerts a reaction force that pushes them back.
This is similar to the example of a runner pushing the ground backward to propel themselves forward. The force exerted by the runner on the ground is the action, and the reaction is the ground pushing the runner forward.
By instinctively applying Newton's third law, the child's outstretched arms experience a reaction force from the ground that helps them to land more safely and prevent a direct impact on their body.